Acquisitions, Intangible Assets and Goodwill (Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite lived intangible assets
Gross Carrying Amount	$ 686,095	$ 712,487
Accumulated Amortization	(458,958)	(440,301)
Net Carrying Amount	227,137	272,186
Amortization expense	44,000	34,000	$ 40,000
Customer relationships
Finite lived intangible assets
Gross Carrying Amount	480,837	504,716
Accumulated Amortization	(281,190)	(271,066)
Net Carrying Amount	199,647	233,650
Software & technology
Finite lived intangible assets
Gross Carrying Amount	165,088	167,122
Accumulated Amortization	(143,877)	(138,724)
Net Carrying Amount	21,211	28,398
Trademarks & other
Finite lived intangible assets
Gross Carrying Amount	40,170	40,649
Accumulated Amortization	(33,891)	(30,511)
Net Carrying Amount	$ 6,279	$ 10,138