Revenue Recognition - Summary of Disaggregated Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 27, 2021	Mar. 28, 2020
Disaggregation Of Revenue [Line Items]
Net sales	$ 288,012	$ 288,012	$ 257,730
U.S. Customers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		273,150	241,392
Non-U.S. Customers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		14,862	16,338
Powertrain [Member]
Disaggregation Of Revenue [Line Items]
Net sales		121,105	108,142
Chassis [Member]
Disaggregation Of Revenue [Line Items]
Net sales		85,510	73,375
Automotive Body [Member]
Disaggregation Of Revenue [Line Items]
Net sales		68,645	64,632
Hardware [Member]
Disaggregation Of Revenue [Line Items]
Net sales		$ 12,752	$ 11,581