Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, gross carrying amount	$ 59,887	$ 60,363
Finite-lived intangible assets, accumulated amortization	(35,245)	(30,900)
Finite-lived intangible assets, net	24,642	29,463
Indefinite-lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-lived intangible assets	518	541
Total intangible assets, gross carrying amount	60,405	60,904
Total intangible assets, net	25,160	30,004
Permits and licenses [Member]
Indefinite-lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-lived intangible assets	518	541
Technology-based intangible assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, gross carrying amount	17,380	15,596
Finite-lived intangible assets, accumulated amortization	(5,509)	(4,427)
Finite-lived intangible assets, net	11,871	11,169
Customer-related intangible assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, gross carrying amount	40,662	42,903
Finite-lived intangible assets, accumulated amortization	(27,891)	(24,679)
Finite-lived intangible assets, net	12,771	18,224
Employment related intangible assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, gross carrying amount	1,845	1,864
Finite-lived intangible assets, accumulated amortization	(1,845)	(1,794)
Finite-lived intangible assets, net	$ 0	$ 70