Segment Reporting and Geographic Locations - Sales by Segment (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
Revenues
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
Gross Profit	10,168	29,444	32,436	33,089	29,248	30,478	34,904	30,290	65,525	65,194	94,969	95,672	105,137	124,920	90,871
Selling, general & administrative expenses	13,571	17,531	16,248	15,199	15,503	15,613	14,349	15,214	31,447	29,563	48,978	45,176	62,549	60,679	59,547
Amortization expense	872	437	322	321	320	321	327	332	643	659	1,080	980	1,952	1,300	1,320
Operating Income	$ (4,275)	$ 11,476	$ 15,866	$ 17,569	$ 13,425	$ 14,544	$ 20,228	$ 14,744	$ 33,435	$ 34,972	$ 44,911	$ 49,516	40,636	62,941	30,004
Capital Expenditures, Depreciation Expense and Other:
Capital expenditures													24,117	15,544	13,567
Depreciation expense													13,562	13,971	13,875
Other items													3,858
Electrical Systems
Revenues
Revenues													522,484	503,717	427,476
Global Seating
Revenues
Revenues													378,754	394,020	327,755
Operating Segments | Electrical Systems
Revenues
Revenues													530,901	512,754	434,398
Gross Profit													60,008	71,104	51,017
Selling, general & administrative expenses													15,815	15,390	15,757
Amortization expense													1,415	747	746
Operating Income													42,778	54,967	34,514
Capital Expenditures, Depreciation Expense and Other:
Capital expenditures													17,728	9,825	6,744
Depreciation expense													6,699	6,919	7,381
Other items													2,159
Operating Segments | Global Seating
Revenues
Revenues													381,548	397,501	329,516
Gross Profit													45,201	54,231	40,722
Selling, general & administrative expenses													20,429	22,433	21,585
Amortization expense													537	553	574
Operating Income													24,235	31,245	18,563
Capital Expenditures, Depreciation Expense and Other:
Capital expenditures													3,721	3,579	4,870
Depreciation expense													4,379	4,604	3,910
Other items													489
Intersegment revenues | Electrical Systems
Revenues
Revenues													(8,417)	(9,037)	(6,922)
Intersegment revenues | Global Seating
Revenues
Revenues													(2,794)	(3,481)	(1,761)
Corporate/ Other
Revenues
Revenues													(11,211)	(12,518)	(8,683)
Gross Profit													(72)	(415)	(868)
Selling, general & administrative expenses													26,305	22,856	22,205
Amortization expense													0	0	0
Operating Income													(26,377)	(23,271)	(23,073)
Capital Expenditures, Depreciation Expense and Other:
Capital expenditures													2,668	2,140	1,953
Depreciation expense													2,484	$ 2,448	$ 2,584
Other items													$ 1,210