Warranties Changes in accrued product warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Standard Product Warranty Accrual [Roll Forward]
Balances at beginning of period	$ 1,633	$ 1,612	$ 3,187
Product Warranty Accrual, Additions from Business Acquisition	0	0	260
Increases to accruals related to sales during the period	1,802	1,071	788
Product Warranty Expense	(1,058)	(1,040)	(2,618)
Product Warranty Accrual, Foreign Exchange Impact	(48)	(10)	(5)
Balances at end of period	$ 2,329	$ 1,633	$ 1,612