Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Sep. 17, 2019	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 437	$ 321	$ 1,080	$ 980
Goodwill [Line Items]
FSE Acquisition			17,675		$ 0
Goodwill	25,188		25,188		$ 7,576		$ 8,045
Global Seating
Goodwill [Line Items]
Goodwill	5,100		5,100
Electrical Systems
Goodwill [Line Items]
Goodwill	$ 20,100		20,100
FSE Acquisition
Goodwill [Line Items]
FSE Acquisition			$ 17,700
Goodwill						$ 17,675