Warranty Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Warranty liability
Period of warranty history used in estimating warranty costs	5 years
Other long-term liabilities	$ 15,652	$ 6,004
Accrued expenses and other current liabilities	27,325	25,549
Company's warranty liability:
Balance at the beginning of the period	7,423	6,279	$ 3,808
Warranty provision	2,452	4,931	4,574
Claims paid/settlements	(3,750)	(3,787)	(2,800)
Balance at the end of the period	6,160	$ 7,423	6,279
Warranty Reserves
Warranty liability
Other long-term liabilities	2,625
Accrued expenses and other current liabilities	3,535
Henderson
Company's warranty liability:
Establish warranty provision for acquisitions			$ 697
Dejana
Company's warranty liability:
Establish warranty provision for acquisitions	$ 35
Snow and ice control equipment
Warranty liability
Warranty period	2 years
Parts and accessories
Warranty liability
Warranty period	1 year
Certain snowplows
Warranty liability
Warranty period	1 year