Intangible Assets and Goodwill (Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Finite lived intangible assets
Gross Carrying Amount	$ 689,551		$ 689,551		$ 686,095
Accumulated Amortization	(476,955)		(476,955)		(458,958)
Net Carrying Amount	212,596		212,596		227,137
Amortization expense	10,000	$ 11,000	21,000	$ 22,000
Customer relationships
Finite lived intangible assets
Gross Carrying Amount	484,597		484,597		480,837
Accumulated Amortization	(294,244)		(294,244)		(281,190)
Net Carrying Amount	190,353		190,353		199,647
Software & technology
Finite lived intangible assets
Gross Carrying Amount	164,849		164,849		165,088
Accumulated Amortization	(147,130)		(147,130)		(143,877)
Net Carrying Amount	17,719		17,719		21,211
Trademarks & other
Finite lived intangible assets
Gross Carrying Amount	40,105		40,105		40,170
Accumulated Amortization	(35,581)		(35,581)		(33,891)
Net Carrying Amount	$ 4,524		$ 4,524		$ 6,279