Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Cost	$ 244,364	$ 258,764
Accumulated Amortization	(136,955)	(125,564)
Accumulated Impairment Loss	(3,814)	(1,025)
Net Intangible Assets	103,595	132,175
Contract and customer-related
Finite-Lived Intangible Assets [Line Items]
Cost	213,194	227,594
Accumulated Amortization	(110,917)	(102,169)
Accumulated Impairment Loss	(3,814)	(1,025)
Net Intangible Assets	98,463	124,400
Acquired technologies
Finite-Lived Intangible Assets [Line Items]
Cost	12,400	12,400
Accumulated Amortization	(10,787)	(9,660)
Accumulated Impairment Loss	0	0
Net Intangible Assets	1,613	2,740
Trade names
Finite-Lived Intangible Assets [Line Items]
Cost	18,770	18,770
Accumulated Amortization	(15,251)	(13,735)
Accumulated Impairment Loss	0	0
Net Intangible Assets	$ 3,519	$ 5,035