Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Net sales	$ 396,753	$ 406,184	[1]	$ 406,039	[1]
Remaining performance obligation	2,900
Change In Contract With Customer Liability [Roll Forward]
Balance, beginning of period	1,084	1,095		315
Cash additions	1,794	2,019		882
Revenue recognition	(2,062)	(2,030)		(102)
Balance, end of period	816	1,084		1,095
United States
Disaggregation of Revenue [Line Items]
Net sales	348,712	352,703		353,893
Canada
Disaggregation of Revenue [Line Items]
Net sales	20,489	25,589		26,005
All other
Disaggregation of Revenue [Line Items]
Net sales	27,552	27,892		26,141
Product sales
Disaggregation of Revenue [Line Items]
Net sales	380,489	388,442		390,833
Extended warranties and services
Disaggregation of Revenue [Line Items]
Net sales	9,226	11,572		7,954
Other
Disaggregation of Revenue [Line Items]
Net sales	7,038	$ 6,170		$ 7,252
Retail Orders
Disaggregation of Revenue [Line Items]
Remaining performance obligation	1,500
Direct Orders
Disaggregation of Revenue [Line Items]
Remaining performance obligation	$ 1,400

[1] See Note 4.