Warranty Liability (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Warranty liability
Period of warranty history used in estimating warranty costs			5 years
Company's warranty liability:
Balance at the beginning of the period	$ 3,568	$ 3,965	$ 3,628	$ 4,188
Establish warranty provision for Trynex			600
Warranty provision	375	293	1,018	1,066
Claims paid/settlements	(62)	(85)	(1,365)	(1,081)
Balance at the end of the period	$ 3,881	$ 4,173	$ 3,881	$ 4,173
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