Product Warranty (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Standard Product Warranty Period [Line Items]
Product warranty liability	$ 575	$ 587
Minimum [Member]
Standard Product Warranty Period [Line Items]
Standard product warranty period	90 days
Maximum [Member]
Standard Product Warranty Period [Line Items]
Standard product warranty period	3 years