CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Income Statement [Abstract]
Product sales	$ 2,338,132	$ 2,824,456	$ 2,976,359
Services sales	280,792	298,687	327,852
Net sales	2,618,924	3,123,143	3,304,211
Product cost of sales	1,804,055	2,118,687	2,144,942
Services cost of sales	193,836	196,339	214,041
Total cost of sales	1,997,891	2,315,026	2,358,983
Gross profit	621,033	808,117	945,228
Selling, general and administrative expenses	447,368	450,401	472,159
Impairment of goodwill and intangible assets	41,970	0	0
Operating income	131,695	357,716	473,069
Other income (expenses):
Interest expense	(44,621)	(36,790)	(32,502)
Interest income	3,296	6,046	6,477
Costs associated with refinancing of debt	0	(38,705)	0
Other	2,637	(4,084)	2,373
Total other income (expenses)	(38,688)	(73,533)	(23,652)
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries	93,007	284,183	449,417
Income tax expense (benefit):
Current	42,569	89,643	167,922
Deferred	4,858	5,251	(10,141)
Total income tax expense (benefit)	47,427	94,894	157,781
Comprehensive income (loss)	(91,836)	99,748	181,633
Earnings before equity in earnings of nonconsolidated subsidiaries	45,580	189,289	291,636
Equity in earnings of nonconsolidated subsidiaries	(247)	29	835
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	0	(12,011)
Net earnings	45,333	189,318	280,460
Less: Earnings attributable to noncontrolling interests	(5,216)	(5,342)	(1,971)
Net earnings attributable to Valmont Industries, Inc.	$ 40,117	$ 183,976	$ 278,489
Earnings per share:
Basic (in dollars per share)	$ 1.72	$ 7.15	$ 10.45
Diluted (in dollars per share)	1.71	7.09	10.35
Cash dividends declared per share (in dollars per share)	$ 1.500	$ 1.375	$ 0.975
Weighted average number of shares of common stock outstanding - Basic (in shares)	23,288	25,719	26,641
Weighted average number of shares of common stock outstanding - Diluted (in shares)	23,405	25,932	26,899