Additional Financial Information Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in warranty and after-sale costs reserve
Balance at beginning of period	$ 1,546	$ 1,199	$ 1,739	$ 882
Net additions charged to earnings	904	592	1,239	1,178
Costs incurred	(90)	(358)	(618)	(627)
Balance at end of period	$ 2,360	$ 1,433	$ 2,360	$ 1,433