Goodwill and Other Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other intangible assets:
Gross Carrying Amount	$ 110,983	$ 121,302
Accumulated Amortization	(50,803)	(54,359)
Net Amount	60,180	66,943
Amortization expense	$ 6,817	6,603	$ 5,815
Finite-Lived Intangible Assets, Remaining Amortization Period	9 years 9 months
Customer lists / relationships
Other intangible assets:
Gross Carrying Amount	$ 64,323	64,323
Accumulated Amortization	(37,088)	(33,685)
Net Amount	$ 27,235	30,638
Finite-Lived Intangible Assets, Remaining Amortization Period	9 years 7 months 6 days
Patents
Other intangible assets:
Gross Carrying Amount		10,319
Accumulated Amortization		(10,319)
Net Amount		0
Technology and other intangibles
Other intangible assets:
Gross Carrying Amount	$ 44,460	44,460
Accumulated Amortization	(13,715)	(10,355)
Net Amount	$ 30,745	34,105
Finite-Lived Intangible Assets, Remaining Amortization Period	10 years 1 month 1 day
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