Segment Reporting and Geographic Locations - Summary Composition by Product Category of Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from External Customer [Line Items]
Revenues	$ 189,485	$ 225,399	$ 243,190	$ 243,164	$ 223,602	$ 225,010	$ 233,391	$ 215,734	$ 486,354	$ 449,125	$ 711,753	$ 674,135	$ 901,238	$ 897,737	$ 755,231
Seats
Revenue from External Customer [Line Items]
Revenues													356,877	369,337	314,717
Electrical wire harnesses, panels and assemblies
Revenue from External Customer [Line Items]
Revenues													198,420	196,411	189,154
Trim
Revenue from External Customer [Line Items]
Revenues													202,898	195,427	150,228
Cab structures and sleeper boxes
Revenue from External Customer [Line Items]
Revenues													87,864	76,380	56,417
Mirrors, wipers and controls
Revenue from External Customer [Line Items]
Revenues													$ 55,179	$ 60,182	$ 44,715
Product Concentration Risk | Revenues
Revenue from External Customer [Line Items]
Percent of net revenues (as a percent)													100.00%	100.00%	100.00%
Product Concentration Risk | Revenues | Seats
Revenue from External Customer [Line Items]
Percent of net revenues (as a percent)													40.00%	41.00%	42.00%
Product Concentration Risk | Revenues | Electrical wire harnesses, panels and assemblies
Revenue from External Customer [Line Items]
Percent of net revenues (as a percent)													22.00%	22.00%	25.00%
Product Concentration Risk | Revenues | Trim
Revenue from External Customer [Line Items]
Percent of net revenues (as a percent)													22.00%	22.00%	20.00%
Product Concentration Risk | Revenues | Cab structures and sleeper boxes
Revenue from External Customer [Line Items]
Percent of net revenues (as a percent)													10.00%	8.00%	7.00%
Product Concentration Risk | Revenues | Mirrors, wipers and controls
Revenue from External Customer [Line Items]
Percent of net revenues (as a percent)													6.00%	7.00%	6.00%