CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Statement of Comprehensive Income [Abstract]
Net earnings	$ 55,001	$ 42,721
Foreign currency translation adjustments:
Unrealized translation gain (loss)	(12,633)	(49,381)
Gain (loss) on hedging activities:
Net investment hedges	0	8,711
Cash flow hedges	22	443
Amortization cost included in interest expense	(16)	(16)
Commodity hedges	9,946	0
Cross currency swaps	3,606	6,302
Actuarial gain (loss)	832	0
Other comprehensive income (loss)	1,757	(33,941)
Comprehensive income	56,758	8,780
Comprehensive loss (income) attributable to noncontrolling interests	486	(297)
Comprehensive income attributable to Valmont Industries, Inc.	$ 57,244	$ 8,483