Restructuring - Summary of Ongoing Restructuring Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	$ 1,500		$ 2,289	$ 1,487	$ 800
Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred		$ 800	2,300
Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		300		100
Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	400		700		100
Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	200		200		200
Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	900		900		200
China
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		0		200
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		200		0
Employee Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred			1,721	$ 37
Employee Costs | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		200		100
Employee Costs | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	200		400		100
Employee Costs | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	200		200		200
Employee Costs | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	800		800		200
Employee Costs | China
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		0		200
Employee Costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		100		0
Employee Costs | Other Restructuring | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		100		0
Facility and Other Costs | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		100		0
Facility and Other Costs | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	200		300		0
Facility and Other Costs | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		0		0
Facility and Other Costs | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	100		100		0
Facility and Other Costs | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		0		$ 0
Minimum
Restructuring Cost and Reserve [Line Items]
Total Expense			8,000
Expected Future Expense	4,900		4,900
Minimum | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			400
Expected Future Expense	0		0
Minimum | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense			1,300
Expected Future Expense	500		500
Minimum | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			1,100
Expected Future Expense	700		700
Minimum | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense			4,400
Expected Future Expense	3,300		3,300
Minimum | China
Restructuring Cost and Reserve [Line Items]
Total Expense			200
Expected Future Expense	0		0
Minimum | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Total Expense			600
Expected Future Expense	400		400
Minimum | Employee Costs | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			300
Expected Future Expense	0		0
Minimum | Employee Costs | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense			600
Expected Future Expense	100		100
Minimum | Employee Costs | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			700
Expected Future Expense	300		300
Minimum | Employee Costs | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense			2,200
Expected Future Expense	1,200		1,200
Minimum | Employee Costs | China
Restructuring Cost and Reserve [Line Items]
Total Expense			200
Expected Future Expense	0		0
Minimum | Employee Costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense			200
Expected Future Expense	100		100
Minimum | Employee Costs | Other Restructuring | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total Expense			100
Expected Future Expense	0		0
Minimum | Facility and Other Costs | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			100
Expected Future Expense	0		0
Minimum | Facility and Other Costs | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense			700
Expected Future Expense	400		400
Minimum | Facility and Other Costs | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			400
Expected Future Expense	400		400
Minimum | Facility and Other Costs | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense			2,200
Expected Future Expense	2,100		2,100
Minimum | Facility and Other Costs | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Total Expense			300
Expected Future Expense	300		300
Maximum
Restructuring Cost and Reserve [Line Items]
Total Expense			11,000
Expected Future Expense	7,900		7,900
Maximum | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			400
Expected Future Expense	0		0
Maximum | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense			1,500
Expected Future Expense	700		700
Maximum | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			1,500
Expected Future Expense	1,100		1,100
Maximum | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense			5,000
Expected Future Expense	3,900		3,900
Maximum | China
Restructuring Cost and Reserve [Line Items]
Total Expense			200
Expected Future Expense	0		0
Maximum | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Total Expense			2,400
Expected Future Expense	2,200		2,200
Maximum | Employee Costs | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			300
Expected Future Expense	0		0
Maximum | Employee Costs | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense			700
Expected Future Expense	200		200
Maximum | Employee Costs | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			900
Expected Future Expense	500		500
Maximum | Employee Costs | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense			2,400
Expected Future Expense	1,400		1,400
Maximum | Employee Costs | China
Restructuring Cost and Reserve [Line Items]
Total Expense			200
Expected Future Expense	0		0
Maximum | Employee Costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense			700
Expected Future Expense	600		600
Maximum | Employee Costs | Other Restructuring | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total Expense			100
Expected Future Expense	0		0
Maximum | Facility and Other Costs | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			100
Expected Future Expense	0		0
Maximum | Facility and Other Costs | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense			800
Expected Future Expense	500		500
Maximum | Facility and Other Costs | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense			600
Expected Future Expense	600		600
Maximum | Facility and Other Costs | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense			2,600
Expected Future Expense	2,500		2,500
Maximum | Facility and Other Costs | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Total Expense			1,600
Expected Future Expense	$ 1,600		$ 1,600