Restructuring - Summary of Ongoing Restructuring Activities (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	$ 748	$ 273	$ 3,500	$ 800
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	0		900	100
Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	100		400	200
Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	600		1,700	200
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		200	200
Employee Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	607	$ 208
Employee Costs | Edgewood Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		200	100
Employee Costs | Piedmont Seating | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		500	100
Employee Costs | Monona Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	100		300	200
Employee Costs | Shadyside Stamping | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	500		1,500	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	200
Facility and other costs | Edgewood Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		100	0
Facility and other costs | Piedmont Seating | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		400	0
Facility and other costs | Monona Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		100	0
Facility and other costs | Shadyside Stamping | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	100		200	0
Facility and other costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	0		$ 0	$ 0
Minimum
Restructuring Cost and Reserve [Line Items]
Total Expense	7,600
Expected Future Expense	2,600
Minimum | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense	400
Expected Future Expense	0
Minimum | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense	1,200
Expected Future Expense	200
Minimum | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense	1,100
Expected Future Expense	400
Minimum | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense	3,500
Expected Future Expense	1,000
Minimum | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Total Expense	1,400
Expected Future Expense	1,000
Minimum | Employee Costs | Edgewood Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	300
Expected Future Expense	0
Minimum | Employee Costs | Piedmont Seating | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	700
Expected Future Expense	100
Minimum | Employee Costs | Monona Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	800
Expected Future Expense	200
Minimum | Employee Costs | Shadyside Stamping | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	2,500
Expected Future Expense	300
Minimum | Employee Costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	600
Expected Future Expense	500
Minimum | Employee Costs | Other Restructuring | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total Expense	300
Expected Future Expense	0
Minimum | Facility and other costs | Edgewood Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	100
Expected Future Expense	0
Minimum | Facility and other costs | Piedmont Seating | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	500
Expected Future Expense	100
Minimum | Facility and other costs | Monona Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	300
Expected Future Expense	200
Minimum | Facility and other costs | Shadyside Stamping | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	1,000
Expected Future Expense	700
Minimum | Facility and other costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	500
Expected Future Expense	500
Maximum
Restructuring Cost and Reserve [Line Items]
Total Expense	10,700
Expected Future Expense	5,700
Maximum | Edgewood Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense	400
Expected Future Expense	0
Maximum | Piedmont Seating
Restructuring Cost and Reserve [Line Items]
Total Expense	1,600
Expected Future Expense	600
Maximum | Monona Wire Harness
Restructuring Cost and Reserve [Line Items]
Total Expense	2,300
Expected Future Expense	1,600
Maximum | Shadyside Stamping
Restructuring Cost and Reserve [Line Items]
Total Expense	4,600
Expected Future Expense	2,100
Maximum | Other Restructuring
Restructuring Cost and Reserve [Line Items]
Total Expense	1,800
Expected Future Expense	1,400
Maximum | Employee Costs | Edgewood Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	300
Expected Future Expense	0
Maximum | Employee Costs | Piedmont Seating | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	900
Expected Future Expense	300
Maximum | Employee Costs | Monona Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	1,400
Expected Future Expense	800
Maximum | Employee Costs | Shadyside Stamping | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	2,800
Expected Future Expense	600
Maximum | Employee Costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	800
Expected Future Expense	700
Maximum | Employee Costs | Other Restructuring | Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total Expense	300
Expected Future Expense	0
Maximum | Facility and other costs | Edgewood Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	100
Expected Future Expense	0
Maximum | Facility and other costs | Piedmont Seating | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	700
Expected Future Expense	300
Maximum | Facility and other costs | Monona Wire Harness | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	900
Expected Future Expense	800
Maximum | Facility and other costs | Shadyside Stamping | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	1,800
Expected Future Expense	1,500
Maximum | Facility and other costs | Other Restructuring | Cost of Revenues
Restructuring Cost and Reserve [Line Items]
Total Expense	700
Expected Future Expense	$ 700