Business Acquisitions - Net Assets Acquired (Details) - USD ($) $ in Thousands	Oct. 28, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Combination, Recognized Identifiable Assets Acquired, Goodwill and Liabilities Assumed, Net
Goodwill		$ 33,865	$ 32,047	$ 32,047
Filter Sensing Technologies Inc.
Business Combination, Recognized Identifiable Assets Acquired, Goodwill and Liabilities Assumed, Net
Current assets	$ 555
Property, plant and equipment	29
Goodwill	1,818
In-process research and development intangible asset	2,200
Other assets	8
Fair value of assets acquired	4,610
Less fair value of liabilities acquired	(1,205)
Less fair value of contingent consideration	(1,550)
Total cash purchase price	$ 1,855