Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Less accumulated depreciation and amortization Payments to Acquire Businesses, Net of Cash Acquired Acquisitions (net of cash acquired of $198,810) Additional Paid in Capital Additional paid-in capital Stock Option Plan Expense Stock option expense Allowance for Doubtful Accounts Receivable, Current Receivables, allowance for doubtful receivables (in dollars) CONDENSED CONSOLIDATED BALANCE SHEETS Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Cash and cash equivalents-beginning of year Cash and cash equivalents-end of period Increase (Decrease) in Deferred Compensation Payment of deferred compensation Increase (Decrease) in Accrued Income Taxes Payable Income taxes payable/refundable Increase (Decrease) in Inventories Inventories Increase (Decrease) in Prepaid Expense Prepaid expenses Increase (Decrease) in Receivables Receivables Proceeds from (Repayments of) Short-term Debt Net payments under short-term agreements Changes in assets and liabilities, net of the effects of acquisitions: Increase (Decrease) in Accounts Payable Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expenses Common Stock, Shares Authorized Common stock, Authorized shares Common Stock, Value, Issued Common stock of $1 par value Authorized 75,000,000 shares; 27,900,000 issued Comprehensive Income, Net of Tax, Attributable to Parent Total comprehensive income Comprehensive Income Comprehensive Income Note [Text Block] Cost of Revenue Cost of sales Current Income Tax Expense (Benefit) Current Current liabilities: Current liabilities: Liabilities, Current Total current liabilities Deferred Income Tax Expense (Benefit) Deferred Deferred income taxes Deferred Tax Assets (Liabilities), Net, Noncurrent Deferred income taxes Derivative Instruments and Hedging Activities Disclosure [Text Block] DERIVATIVE FINANCIAL INSTRUMENTS Earnings Per Share, Diluted Earnings per share attributable to Valmont Industries, Inc.-Diluted (in dollars per share) Income (Loss) from Equity Method Investments Equity in earnings (losses) of nonconsolidated subsidiaries Equity in earnings (losses) of nonconsolidated subsidiaries Effect of Exchange Rate on Cash and Cash Equivalents Effect of exchange rate changes on cash and cash equivalents Share-based Compensation Stock-based compensation Gain (Loss) on Sale of Property Plant Equipment Loss on sales of property, plant and equipment Gross Profit Gross profit CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS Income Tax Disclosure [Text Block] INCOME TAXES Intangible Assets, Net (Excluding Goodwill) Other intangible assets, net Interest Expense Interest expense Inventory, Net Inventories LIABILITIES AND SHAREHOLDERS' EQUITY LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Stockholders' Equity Total liabilities and shareholders' equity Long-term Debt, Current Maturities Current installments of long-term debt Long-term Debt, Excluding Current Maturities Long-term debt, excluding current installments Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Dividends to noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Noncontrolling interest in consolidated subsidiaries Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities Net cash flows from financing activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities Net cash flows from investing activities Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities Net cash flows from operating activities Net Income (Loss) Attributable to Parent Net earnings attributable to Valmont Industries, Inc. Net earnings Cash and Cash Equivalents, Period Increase (Decrease) Net change in cash and cash equivalents Proceeds from Stock Plans Proceeds from exercises under stock plans Other income (expenses): Other income (expenses): Nonoperating Income (Expense) Total other income (expenses) Notes Payable to Bank, Current Notes payable to banks Operating Income (Loss) Operating income Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax Currency translation adjustment Payments for (Proceeds from) Other Investing Activities Other, net Miscellaneous Other Nonoperating Income (Expense) Other Payments of Dividends, Common Stock Dividends paid Payments of Dividends, Noncontrolling Interest Dividends to noncontrolling interests Pension and Other Postretirement Benefits Disclosure [Text Block] Defined Benefit Retirement Plan Preferred Stock, Shares Authorized Preferred stock, Authorized shares Preferred Stock, Shares Issued Preferred stock, issued shares Prepaid Expense, Current Prepaid expenses and other current assets Proceeds from Sale of Treasury Stock Purchase of treasury shares Proceeds from Issuance of Long-term Debt Proceeds from long-term borrowings Proceeds from Sale of Productive Assets Proceeds from sale of assets Property, Plant and Equipment, Gross Property, plant and equipment, at cost Property, Plant and Equipment, Net Net property, plant and equipment Payments to Acquire Interest in Subsidiaries and Affiliates Investments in and advances to nonconsolidated subsidiary Payments to Acquire Property, Plant, and Equipment Purchase of property, plant and equipment Receivables, Net, Current Receivables, net Repayments of Long-term Debt Principal payments on long-term obligations Payments for Repurchase of Common Stock Purchase of common treasury shares-stock plan exercises Research, Development, and Computer Software Disclosure [Text Block] RESEARCH AND DEVELOPMENT Retained Earnings (Accumulated Deficit) Retained earnings Sales Revenue, Net Net sales Schedule of Guarantor Obligations [Text Block] GUARANTEES Inventory Disclosure [Text Block] INVENTORIES Schedule of Line of Credit Facilities [Text Block] BANK CREDIT ARRANGEMENTS Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Valuation and Qualifying Accounts Segment Reporting Disclosure [Text Block] Business Segments Selling, General and Administrative Expense Selling, general and administrative expenses Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY Stockholders' Equity Attributable to Parent [Abstract] Shareholders' equity: Goodwill and Intangible Assets Disclosure [Text Block] Goodwill and Intangible Assets Current assets: Current assets: Assets, Current Total current assets Treasury stock Stock Issued During Period, Shares, Treasury Stock Reissued Sale of treasury shares, shares Stock Issued During Period, Value, Treasury Stock Reissued Sale of 18,967, 147 treasury shares during 2007 and 2008 respectively Weighted average number of shares of common stock outstanding-Diluted (000 omitted) (in shares) Weighted Average Number of Shares Outstanding, Diluted Weighted average number of shares of common stock outstanding-Basic (000 omitted) (in shares) Weighted Average Number of Shares Outstanding, Basic Common stock Property, Plant and Equipment Disclosure [Text Block] PROPERTY, PLANT AND EQUIPMENT Dividends Payable, Amount Dividends payable Unearned restricted stock Assets. Total assets Investment Income, Interest Interest income Other Liabilities, Noncurrent Other noncurrent liabilities Disclosure of Compensation Related Costs, Share-based Payments [Text Block] STOCK PLANS Statement [Table] ASSETS ASSETS Statement Fair Value Disclosures [Text Block] DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS QUARTERLY FINANCIAL DATA Quarterly Financial Information [Text Block] Treasury Stock, Value Cost of common shares in treasury 1,602,860 shares in 2009 (1,731,771 shares in 2008) Treasury stock Cash Flow, Supplemental Disclosures [Text Block] Cash Flows Earnings Per Share, Basic Earnings per share attributable to Valmont Industries, Inc.-Basic (in dollars per share) Excess Tax Benefit from Share-based Compensation, Financing Activities Excess tax benefits from stock option exercises Increase (Decrease) in Shareholders' Equity Stockholders' Equity, Period Increase (Decrease) Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Accumulated other comprehensive income (loss) Schedule of Treasury Stock by Class [Text Block] TREASURY STOCK Preferred Stock, Par or Stated Value Per Share Preferred stock, par value (in dollars per share) Common Stock, Shares, Issued Common stock, issued shares Other Assets, Noncurrent Other assets Earnings per share: Earnings per share: Increase (Decrease) in Other Operating Liabilities Other noncurrent liabilities Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Treasury Stock, Shares Common shares in treasury Stockholders' Equity Attributable to Parent Total Valmont Industries, Inc. shareholders' equity Income tax expense (benefit): Income Tax Expense (Benefit). Total income tax expense Short-term Bank Loans and Notes Payable Notes payable to banks Preferred Stock, Value, Issued Preferred stock Authorized 500,000 shares; none issued Cash dividends, per share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Purchase of noncontrolling interest Tax Benefit from Stock Options Exercised Tax benefit from exercise of stock options Statement, Equity Components [Axis] Additional paid-in capital Retained earnings Accumulated other comprehensive income (loss) Equity Component [Domain] Long-term Debt [Text Block] Long-term Debt Goodwill Goodwill Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Stock awards; 45,540 shares issued in 2006; 26,332 shares issued in 2007 and 11,030 shares issued in 2008 Stock Issued During Period, Value, Stock Options Exercised Stock options exercised; 72,075 and 121,345 shares issued for the periods 2010 and 2009 respectively Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Stock awards; shares issued Stock Issued During Period, Shares, Stock Options Exercised Stock options exercised; shares issued Treasury Stock, Shares, Acquired Purchase of treasury shares, shares Schedule of Condensed Financial Statements [Text Block] Guarantor/Non-Guarantor Financial Information Treasury Stock, Value, Acquired, Cost Method Purchase of 12,351 treasury shares Earnings Per Share [Text Block] Earnings Per Share Net earnings Net earnings Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net Income (Loss) Attributable to Noncontrolling Interest Less: Earnings attributable to noncontrolling interests Depreciation, Depletion and Amortization Depreciation and amortization Comprehensive income: Total comprehensive income Comprehensive Income, Net of Tax, Including Portion Attributable to Noncontrolling Interest Shareholders' equity: Total shareholders' equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Balance Balance Accounts Payable, Current Accounts payable Accrued Liabilities, Current Accrued expenses Employee-related Liabilities, Current Accrued employee compensation and benefits Noncontrolling interest in consolidated subsidiaries Commitments and Contingencies Commitments and contingencies Dividends, Common Stock, Cash Cash dividends ($0.315 and $0.28 per share for the periods 2010 and 2009 respectively) Adjustments to reconcile net earnings to net cash flow from operations: Adjustments to reconcile net earnings to net cash flows from operations: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities, Other Other Earnings before minority interest and equity in earnings/(losses) of nonconsolidated subsidiaries Income (Loss) from Continuing Operations before Minority Interest and Income (Loss) from Equity Method Investments Sum of operating profit and nonoperating income (expense) after income taxes and before income (loss) from equity method investments and noncontrolling interest. Earnings before equity in earnings (losses) of nonconsolidated subsidiaries Document and Entity Information Refundable and deferred income taxes Income Taxes Receivable and Deferred Tax Assets Liabilities, Net, Current Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also includes the net amount of deferred tax assets (after reduction for valuation allowance) and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities that are classified as current in the financial statements, or that are expected to reverse in the next twelve months (or normal operating cycle, if longer), for entities that net deferred tax assets and tax liabilities. A temporary diffe rence is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods. In a classified statement of financial position, an enterprise shall separate deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets shall be classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, shall be classified according to the expected reversal date of the temporary difference. Current installments of long-term debt Long Term Debt, Current, Excluding Notes Payable to Bank, Current Total of the portions of the carrying amounts as of the balance sheet date of long-term debt, which are scheduled to be repaid within one year or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any. This does not include all notes payable to banks paid on an installment with long term maturities. Adoption of SFAS No. 123R Cumulative Effect of Initial Adoption of SFAS 123R Cumulative-effect adjustment upon the initial adoption of Statement of Financial Accounting Standard No. 123R (FAS No. 123R). Purchase of treasury shares: Treasury Stock [Abstract] Valuation and Qualifying Accounts Stock awards; 9,088 and 9,746 shares issued for the periods 2010 and 2009 respectively Stock Issued Value Restricted Stock Units Long-term Incentive Payments in Shares Value of shares issued during the period related to vested restricted stock unit awards and payment of certain long-term management incentives in shares. In addition, this line item includes the amortization associated with restricted stock awards. Increase (Decrease) in Accrued Income Taxes Payable Receivable The net change during the period in the amount of cash payments due to taxing authorities for taxes that are based on the reporting entity's earnings and in income taxes receivable, which represents the amount due from tax authorities for refunds of overpayments or recoveries of income taxes paid. Stock plan exercises; 27,230 and 33,481 shares purchased for the periods 2010 and 2009 respectively Cost of common and preferred stock that were purchased during the period for the stock plan. Recorded using the cost method. Treasury Stock Value Acquired Stock Plan Cost Method Stock plan exercises; shares purchased Number of shares repurchased during the period to be used for the stock plan and are being held in treasury. Treasury Stock Shares Acquired Stock Plan Summary of Significant Accounting Policies Acquisition of Delta plc Goodwill and Intangible Assets Cash Flows Earnings Per Share Comprehensive Income. Business Segments Guarantor/Non-Guarantor Financial Information INVENTORIES PROPERTY, PLANT AND EQUIPMENT BANK CREDIT ARRANGEMENTS INCOME TAXES Long-term Debt STOCK PLANS TREASURY STOCK. Defined Benefit Retirement Plan RESEARCH AND DEVELOPMENT DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS DERIVATIVE FINANCIAL INSTRUMENTS GUARANTEES QUARTERLY FINANCIAL DATA Common Stock, Dividends, Per Share, Declared Cash dividends per share (in dollars per share) Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Text Block] Acquisition of Delta plc Restricted Cash and Cash Equivalents, Current Restricted cash Increase (Decrease) in Restricted Cash Cash restricted for acquisitions Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Less: Loss from discontinued operations, net of tax Defined Benefit Pension Plan, Liabilities, Noncurrent Defined benefit pension liability Stock Issued During Period, Value, Acquisitions Acquisition of Delta plc Statement, Scenario [Axis] Scenario, Unspecified [Domain] Deferred Compensation Liability, Classified, Noncurrent Deferred compensation Cash acquired from Acquisition Acquisitions, cash acquired Debt issuance costs Payment of Debt Issuance Costs Comprehensive Income Prepaid expenses and other current assets Prepaid Expense and Other Current Assets Sum of the carrying amount of expenditures made in advance of when the economic benefit of the cost will be realized, and which will be expensed in future periods with the passage of time or when a triggering event occurs and the carrying amount as of the balance sheet date of assets not otherwise specified in the taxonomy. Also includes assets not individually reported in the financial statements, or not separately disclosed in notes.