Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 61,708	$ 91,057	$ 205,112	$ 281,368
Remaining performance obligation	5,900		5,900
Change In Contract With Customer Liability [Roll Forward]
Balance, beginning of period	562	748	816	1,084
Cash additions	611	354	1,123	1,347
Revenue recognition	(279)	(227)	(1,045)	(1,556)
Balance, end of period	894	875	894	875
United States
Disaggregation of Revenue [Line Items]
Net sales	50,447	81,423	169,532	250,502
Canada
Disaggregation of Revenue [Line Items]
Net sales	5,649	4,306	17,135	13,372
All other
Disaggregation of Revenue [Line Items]
Net sales	5,612	5,328	18,445	17,494
Product sales
Disaggregation of Revenue [Line Items]
Net sales	59,323	88,068	195,781	269,288
Extended warranties and services
Disaggregation of Revenue [Line Items]
Net sales	993	1,611	4,630	6,830
Other
Disaggregation of Revenue [Line Items]
Net sales	1,392	$ 1,378	4,701	$ 5,250
Retail Orders
Disaggregation of Revenue [Line Items]
Remaining performance obligation	5,300		5,300
Direct Orders
Disaggregation of Revenue [Line Items]
Remaining performance obligation	$ 600		$ 600