Goodwill and Identifiable Intangible Assets - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 80,241	$ 89,265
Accumulated Amortization	(23,800)	(28,684)
Net Carrying Amount	56,441	60,581
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	65,658	73,458
Accumulated Amortization	(12,902)	(17,025)
Net Carrying Amount	52,756	56,433
Developed technologies
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,728	7,461
Accumulated Amortization	(5,929)	(6,446)
Net Carrying Amount	799	1,015
Trade name and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,855	8,346
Accumulated Amortization	(4,969)	(5,213)
Net Carrying Amount	$ 2,886	$ 3,133