Guarantees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Guarantees [Abstract]
Standard warranty period (in years)	1 year
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 2,509	$ 2,286	$ 2,422
Provision for warranties	2,967	3,836	3,492
Claims made	(3,522)	(3,613)	(3,628)
Ending balance	$ 1,954	$ 2,509	$ 2,286