CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 01, 2017	Mar. 26, 2016
Income Statement [Abstract]
Product sales	$ 572,952	$ 532,940
Services sales	64,521	63,665
Net sales	637,473	596,605
Product cost of sales	426,847	393,492
Services cost of sales	46,021	42,144
Total cost of sales	472,868	435,636
Gross profit	164,605	160,969
Selling, general and administrative expenses	100,103	98,604
Operating income	64,502	62,365
Other income (expenses):
Interest expense	(11,304)	(11,054)
Interest income	927	811
Other	1,199	(1,678)
Total other income (expenses)	(9,178)	(11,921)
Earnings before income taxes	55,324	50,444
Income tax expense:
Current	1,298	10,514
Deferred	14,065	5,759
Total income tax expense (benefit)	15,363	16,273
Earnings before equity in earnings of nonconsolidated subsidiaries	39,961	34,171
Equity in earnings of nonconsolidated subsidiaries	0	0
Net earnings	39,961	34,171
Less: Earnings attributable to noncontrolling interests	(982)	(1,202)
Net earnings attributable to Valmont Industries, Inc.	$ 38,979	$ 32,969
Earnings per share:
Basic (in dollars per share)	$ 1.73	$ 1.45
Diluted (in dollars per share)	1.72	1.45
Cash dividends declared per share (in dollars per share)	$ 0.375	$ 0.375
Weighted average number of shares of common stock outstanding - Basic (in shares)	22,472	22,700
Weighted average number of shares of common stock outstanding - Diluted (in shares)	22,660	22,816