Goodwill and Other Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other intangible assets:
Gross Carrying Amount	$ 121,302	$ 112,620
Accumulated Amortization	(54,359)	(48,250)
Net Amount	66,943	64,370
Amortization expense	$ 6,603	5,815	$ 4,035
Finite-Lived Intangible Assets, Remaining Amortization Period	10 years 6 months
Customer lists / relationships
Other intangible assets:
Gross Carrying Amount	$ 64,323	63,386
Accumulated Amortization	(33,685)	(30,318)
Net Amount	$ 30,638	33,068
Finite-Lived Intangible Assets, Remaining Amortization Period	10 years 6 months
Patents
Other intangible assets:
Gross Carrying Amount	$ 10,319	10,319
Accumulated Amortization	(10,319)	(10,319)
Net Amount	0	0
Technology and other intangibles
Other intangible assets:
Gross Carrying Amount	44,460	36,715
Accumulated Amortization	(10,355)	(7,613)
Net Amount	$ 34,105	29,102
Finite-Lived Intangible Assets, Remaining Amortization Period	8 years 4 months
In process research and development
Other intangible assets:
Gross Carrying Amount	$ 2,200	2,200
Accumulated Amortization	0	0
Net Amount	$ 2,200	$ 2,200