CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Statement of Comprehensive Income [Abstract]
Net earnings	$ 22,754	$ 40,668	$ 65,475	$ 77,746
Foreign currency translation adjustments:
Unrealized translation gain (loss)	18,888	1,049	(30,493)	3,315
Gain (loss) on hedging activities:
Net investment hedges	(1,427)	711	7,284	780
Cash flow hedges	(73)	0	370	0
Amortization cost included in interest expense	(16)	(16)	(32)	(32)
Commodity hedges	0	(2,109)	0	(2,109)
Cross currency swaps	(2,007)	(3,933)	4,295	(1,672)
Other comprehensive income (loss)	15,365	(4,298)	(18,576)	282
Comprehensive income	38,119	36,370	46,899	78,028
Comprehensive income attributable to noncontrolling interests	(130)	(983)	(427)	(2,092)
Comprehensive income attributable to Valmont Industries, Inc.	$ 37,989	$ 35,387	$ 46,472	$ 75,936