GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	$ 189,318	$ 280,460	$ 238,916
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	(82,275)	(71,698)	15,741
Realized loss on sale of investment in foreign entity included in other expense		5,194
Realized loss on deconsolidation of subsidiary		8,559
Foreign currency translation adjustments	(82,275)	(57,945)	15,741
Unrealized loss on cash flow hedge:
Loss arising during the period	983
Gain (deferred) on cash flow hedges	4,837
Amortization cost included in interest expense	594	400	400
Derivative adjustment	6,414	400	400
Actuarial gain (loss) in defined benefit pension plan liability	(13,709)	(41,282)	(35,020)
Other comprehensive income (loss)	(89,570)	(98,827)	(18,879)
Comprehensive income	99,748	181,633	220,037
Comprehensive income attributable to noncontrolling interests	(2,520)	(9,174)	(6,079)
Comprehensive income attributable to Valmont Industries, Inc.	97,228	172,459	213,958
Parent
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	183,976	278,489	234,072
Unrealized loss on cash flow hedge:
Loss arising during the period	983
Gain (deferred) on cash flow hedges	4,837
Amortization cost included in interest expense	594	400	400
Derivative adjustment	6,414	400	400
Equity in other comprehensive income	(93,162)	(106,430)	(20,514)
Other comprehensive income (loss)	(86,748)	(106,030)	(20,114)
Comprehensive income	97,228	172,459	213,958
Comprehensive income attributable to Valmont Industries, Inc.	97,228	172,459	213,958
Guarantors
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	67,725	97,955	88,746
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	(51,536)	(4,772)	884
Foreign currency translation adjustments	(51,536)	(4,772)	884
Unrealized loss on cash flow hedge:
Other comprehensive income (loss)	(51,536)	(4,772)	884
Comprehensive income	16,189	93,183	89,630
Comprehensive income attributable to Valmont Industries, Inc.	16,189	93,183	89,630
Non-Guarantors
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	85,840	68,597	83,263
Foreign currency translation adjustments:
Unrealized gains (losses) arising during the period	(30,739)	(66,926)	14,857
Realized loss on sale of investment in foreign entity included in other expense		5,194
Realized loss on deconsolidation of subsidiary		8,559
Foreign currency translation adjustments	(30,739)	(53,173)	14,857
Unrealized loss on cash flow hedge:
Actuarial gain (loss) in defined benefit pension plan liability	(13,709)	(41,282)	(35,020)
Other comprehensive income (loss)	(44,448)	(94,455)	(20,163)
Comprehensive income	41,392	(25,858)	63,100
Comprehensive income attributable to noncontrolling interests	(2,520)	(9,174)	(6,079)
Comprehensive income attributable to Valmont Industries, Inc.	38,872	(35,032)	57,021
Eliminations
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net earnings	(148,223)	(164,581)	(167,165)
Unrealized loss on cash flow hedge:
Equity in other comprehensive income	93,162	106,430	20,514
Other comprehensive income (loss)	93,162	106,430	20,514
Comprehensive income	(55,061)	(58,151)	(146,651)
Comprehensive income attributable to Valmont Industries, Inc.	$ (55,061)	$ (58,151)	$ (146,651)