Revenue and Segment Information - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Net Sales	$ 257,572	$ 240,455	$ 752,784	$ 669,120
Wholegoods
Disaggregation of Revenue [Line Items]
Net Sales	204,349	187,696	604,073	528,807
Parts
Disaggregation of Revenue [Line Items]
Net Sales	47,911	48,302	135,153	128,927
Other
Disaggregation of Revenue [Line Items]
Net Sales	$ 5,312	$ 4,457	$ 13,558	$ 11,386