CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Income Statement [Abstract]
Product sales	$ 560,518	$ 686,508	$ 1,776,194	$ 2,134,395
Services sales	72,057	79,160	208,902	225,612
Net sales	632,575	765,668	1,985,096	2,360,007
Product cost of sales	427,688	515,217	1,348,402	1,586,127
Services cost of sales	48,136	50,951	144,941	146,921
Total cost of sales	475,824	566,168	1,493,343	1,733,048
Gross profit	156,751	199,500	491,753	626,959
Selling, general and administrative expenses	104,539	111,697	327,858	335,532
Impairment of goodwill and intangible assets	15,200	0	15,200	0
Operating income	37,012	87,803	148,695	291,427
Other income (expenses):
Interest expense	(11,120)	(8,716)	(33,480)	(25,217)
Interest income	905	1,477	2,395	4,793
Costs associated with refinancing of debt	0	(38,705)	0	(38,705)
Other	(1,230)	(2,344)	(242)	(6,253)
Total other income (expenses)	(11,445)	(48,288)	(31,327)	(65,382)
Earnings before income taxes	25,567	39,515	117,368	226,045
Income tax expense (benefit):
Current	6,746	23,290	37,656	82,345
Deferred	5,272	(9,064)	5,217	(4,034)
Total income tax expense (benefit)	12,018	14,226	42,873	78,311
Earnings before equity in earnings of nonconsolidated subsidiaries	13,549	25,289	74,495	147,734
Equity in earnings of nonconsolidated subsidiaries	0	(4)	0	(34)
Net earnings	13,549	25,285	74,495	147,700
Less: Earnings attributable to noncontrolling interests	(1,483)	(1,726)	(3,817)	(4,185)
Net earnings attributable to Valmont Industries, Inc.	$ 12,066	$ 23,559	$ 70,678	$ 143,515
Earnings per share:
Basic (in dollars per share)	$ 0.52	$ 0.93	$ 3.02	$ 5.48
Diluted (in dollars per share)	0.52	0.92	3.00	5.43
Cash dividends declared per share (in dollars per share)	$ 0.375	$ 0.375	$ 1.125	$ 1
Weighted average number of shares of common stock outstanding - Basic (in shares)	23,057	25,287	23,420	26,208
Weighted average number of shares of common stock outstanding - Diluted (in shares)	23,170	25,513	23,534	26,439