Commitments and Contingencies - Roll Forward Of The Warranty Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Beginning balance January 1	$ 5,628	$ 7,936	$ 7,196
Provision for warranties	2,895	1,828	4,788
Claim settlements	(2,317)	(3,539)	(3,864)
Other adjustments, including acquisitions, divestitures and currency translation	75	(597)	(184)
Ending balance December 31	$ 6,281	$ 5,628	$ 7,936