GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Dec. 25, 2010
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	$ 238,916	$ 237,226	$ 100,413
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	15,741	(21,976)	20,748
Realized loss on sale of foreign entity investment included in other expense		1,446
Foreign currency translation adjustment	15,741	(20,530)	20,748
Unrealized loss on cash flow hedge:
Loss arising during the period		(3,568)
Amortization cost included in interest expense	400	233
Derivative adjustment	400	(3,335)
Actuarial gain (loss) in defined benefit pension plan liability	(35,020)	22,365	28,952
Other comprehensive income (loss)	(18,879)	(1,500)	49,700
Comprehensive income	220,037	235,726	150,113
Comprehensive income attributable to noncontrolling interests	(6,079)	(7,011)	(9,042)
Comprehensive income attributable to Valmont Industries, Inc.	213,958	228,715	141,071
Parent
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	234,072	228,308	94,379
Unrealized loss on cash flow hedge:
Loss arising during the period		(3,568)
Amortization cost included in interest expense	400	233
Derivative adjustment	400	(3,335)
Equity in other comprehensive income	(20,514)	3,742	46,692
Other comprehensive income (loss)	(20,114)	407	46,692
Comprehensive income	213,958	228,715	141,071
Comprehensive income attributable to Valmont Industries, Inc.	213,958	228,715	141,071
Guarantors
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	96,982	142,900	40,148
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	(14,422)	(958)
Foreign currency translation adjustment	(14,422)	(958)
Unrealized loss on cash flow hedge:
Other comprehensive income (loss)	(14,422)	(958)
Comprehensive income	82,560	141,942	40,148
Comprehensive income attributable to Valmont Industries, Inc.	82,560	141,942	40,148
Non-Guarantors
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	123,333	164,422	54,943
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	30,163	(21,018)	20,748
Realized loss on sale of foreign entity investment included in other expense		1,446
Foreign currency translation adjustment	30,163	(19,572)	20,748
Unrealized loss on cash flow hedge:
Actuarial gain (loss) in defined benefit pension plan liability	(35,020)	22,365	28,952
Other comprehensive income (loss)	(4,857)	2,793	49,700
Comprehensive income	118,476	167,215	104,643
Comprehensive income attributable to noncontrolling interests	(6,079)	(7,011)	(9,042)
Comprehensive income attributable to Valmont Industries, Inc.	112,397	160,204	95,601
Eliminations
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	(215,471)	(298,404)	(89,057)
Unrealized loss on cash flow hedge:
Equity in other comprehensive income	20,514	(3,742)	(46,692)
Other comprehensive income (loss)	20,514	(3,742)	(46,692)
Comprehensive income	(194,957)	(302,146)	(135,749)
Comprehensive income attributable to Valmont Industries, Inc.	$ (194,957)	$ (302,146)	$ (135,749)