Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accrued Expenses and Other Current Liabilities
Payroll and related costs	$ 7,104	$ 8,731
Employee benefits	4,947	5,179
Accrued warranty	3,364	3,535
Earnout - Dejana		5,487
Other	5,334	4,393
Accrued expenses and other current liabilities	$ 20,749	$ 27,325