CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Statement of Comprehensive Income [Abstract]
Net earnings	$ 52,253	$ 40,228	$ 169,911	$ 105,703
Foreign currency translation adjustments:
Unrealized translation gain (loss)	(15,018)	14,391	(16,961)	(16,102)
Gain (loss) on hedging activities:
Net investment hedges	0	0	0	7,284
Cash flow hedges	307	(26)	16	344
Amortization cost included in interest expense	(16)	(16)	(48)	(48)
Commodity hedges	(5,754)	0	20,500	0
Realized gain on commodity hedges recorded in earnings	(9,870)	0	(10,140)	0
Cross currency swaps	2,530	(3,725)	4,041	570
Defined Benefit Pension Plan:
Actuarial loss	163	0	1,838	0
Other comprehensive income (loss)	(27,658)	10,624	(754)	(7,952)
Comprehensive income	24,595	50,852	169,157	97,751
Comprehensive (income) loss attributable to noncontrolling interests	268	(1,358)	(819)	(1,785)
Comprehensive income attributable to Valmont Industries, Inc.	$ 24,863	$ 49,494	$ 168,338	$ 95,966