GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Mar. 30, 2013	Jun. 28, 2014	Jun. 29, 2013
Condensed consolidated financial information for the Company (Parent), the Guarantor subsidiaries and the Non-Guarantor subsidiaries
Net earnings	$ 65,852	$ 91,316		$ 122,415	$ 169,456
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	13,869	(52,962)		25,506	(62,582)
Realized loss included in net earnings during the period			(5,194)		(5,194)
Foreign currency translation adjustments	13,869	(52,962)		25,506	(67,776)
Unrealized loss on cash flow hedge:
Amortization cost included in interest expense	(33)	100		67	200
Derivative adjustment	(33)	100		67	200
Actuarial gain (loss) in defined benefit pension plan liability	(614)	42		(847)	(894)
Other comprehensive income (loss)	13,222	(52,820)		24,726	(68,470)
Comprehensive income	79,074	38,496		147,141	100,986
Comprehensive income attributable to noncontrolling interests	(1,792)	1,549		(1,704)	3,189
Comprehensive income attributable to Valmont Industries, Inc.	77,282	40,045		145,437	104,175
Parent
Condensed consolidated financial information for the Company (Parent), the Guarantor subsidiaries and the Non-Guarantor subsidiaries
Net earnings	63,976	89,563		119,956	167,132
Unrealized loss on cash flow hedge:
Amortization cost included in interest expense	100	100		200	200
Derivative adjustment	100	100		200	200
Equity in other comprehensive income	13,206	(49,618)		25,281	(63,157)
Other comprehensive income (loss)	13,306	(49,518)		25,481	(62,957)
Comprehensive income	77,282	40,045		145,437	104,175
Comprehensive income attributable to Valmont Industries, Inc.	77,282	40,045		145,437	104,175
Guarantors
Condensed consolidated financial information for the Company (Parent), the Guarantor subsidiaries and the Non-Guarantor subsidiaries
Net earnings	21,422	32,003		37,087	59,510
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	(8,954)	65,807		(29,315)	27,486
Foreign currency translation adjustments	(8,954)	65,807		(29,315)	27,486
Unrealized loss on cash flow hedge:
Other comprehensive income (loss)	(8,954)	65,807		(29,315)	27,486
Comprehensive income	12,468	97,810		7,772	86,996
Comprehensive income attributable to Valmont Industries, Inc.	12,468	97,810		7,772	86,996
Non-Guarantors
Condensed consolidated financial information for the Company (Parent), the Guarantor subsidiaries and the Non-Guarantor subsidiaries
Net earnings	35,886	38,550		53,986	67,811
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	22,823	(118,769)		54,821	(90,068)
Realized loss included in net earnings during the period					(5,194)
Foreign currency translation adjustments	22,823	(118,769)		54,821	(95,262)
Unrealized loss on cash flow hedge:
Amortization cost included in interest expense	(133)			(133)
Derivative adjustment	(133)			(133)
Actuarial gain (loss) in defined benefit pension plan liability	(614)	42		(847)	(894)
Other comprehensive income (loss)	22,076	(118,727)		53,841	(96,156)
Comprehensive income	57,962	(80,177)		107,827	(28,345)
Comprehensive income attributable to noncontrolling interests	(1,792)	1,549		(1,704)	3,189
Comprehensive income attributable to Valmont Industries, Inc.	56,170	(78,628)		106,123	(25,156)
Eliminations
Condensed consolidated financial information for the Company (Parent), the Guarantor subsidiaries and the Non-Guarantor subsidiaries
Net earnings	(55,432)	(68,800)		(88,614)	(124,997)
Unrealized loss on cash flow hedge:
Equity in other comprehensive income	(13,206)	49,618		(25,281)	63,157
Other comprehensive income (loss)	(13,206)	49,618		(25,281)	63,157
Comprehensive income	(68,638)	(19,182)		(113,895)	(61,840)
Comprehensive income attributable to Valmont Industries, Inc.	$ (68,638)	$ (19,182)		$ (113,895)	$ (61,840)