CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015
Income Statement [Abstract]
Product sales	$ 544,828	$ 560,518	$ 1,648,530	$ 1,776,194
Services sales	65,419	72,057	198,571	208,902
Net sales	610,247	632,575	1,847,101	1,985,096
Product cost of sales	409,003	427,688	1,220,567	1,348,402
Services cost of sales	46,221	48,136	135,425	144,941
Total cost of sales	455,224	475,824	1,355,992	1,493,343
Gross profit	155,023	156,751	491,109	491,753
Selling, general and administrative expenses	101,783	104,539	303,698	327,858
Impairment of goodwill and intangible assets	0	15,200	0	15,200
Operating income	53,240	37,012	187,411	148,695
Other income (expenses):
Interest expense	(11,100)	(11,120)	(33,276)	(33,480)
Interest income	771	905	2,289	2,395
Other	878	(1,230)	452	(242)
Total other income (expenses)	(9,451)	(11,445)	(30,535)	(31,327)
Earnings before income taxes	43,789	25,567	156,876	117,368
Income tax expense (benefit):
Current	18,017	6,746	51,276	37,656
Deferred	(3,749)	5,272	(1,534)	5,217
Total income tax expense (benefit)	14,268	12,018	49,742	42,873
Earnings before equity in earnings of nonconsolidated subsidiaries	29,521	13,549	107,134	74,495
Equity in earnings of nonconsolidated subsidiaries	0	0	0	0
Net earnings	29,521	13,549	107,134	74,495
Less: Earnings attributable to noncontrolling interests	(1,348)	(1,483)	(3,966)	(3,817)
Net earnings attributable to Valmont Industries, Inc.	$ 28,173	$ 12,066	$ 103,168	$ 70,678
Earnings per share:
Basic (in dollars per share)	$ 1.25	$ 0.52	$ 4.56	$ 3.02
Diluted (in dollars per share)	1.24	0.52	4.54	3.00
Cash dividends declared per share (in dollars per share)	$ 0.375	$ 0.375	$ 1.125	$ 1.125
Weighted average number of shares of common stock outstanding - Basic (in shares)	22,505	23,057	22,602	23,420
Weighted average number of shares of common stock outstanding - Diluted (in shares)	22,659	23,170	22,741	23,534