Revenue Recognition - Summary of Disaggregated Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Disaggregation Of Revenue [Line Items]
Net Sales	$ 257,730	$ 243,791
U.S. Customers [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	241,392	227,151
Non-U.S. Customers [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	16,338	16,640
Powertrain [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	108,142	95,163
Chassis [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	73,375	77,406
Automotive Body [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	64,632	60,746
Hardware [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	$ 11,581	$ 10,476