Goodwill Goodwill and Intangible Assets - Intangible Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Years		Dec. 31, 2014 USD ($)
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 593,037	$ 613,390
Accumulated amortization	(256,155)	(224,064)
Intangible assets, net	336,882	389,326
Impairment of Intangible Assets (Excluding Goodwill)				$ 78,000
Amortization of Intangible Assets	54,886	$ 51,036		$ 44,063
Future Amortization Expense, Year One	49,386
Future Amortization Expense, Year Two	43,245
Future Amortization Expense, Year Three	36,929
Future Amortization Expense, Year Four	29,973
Future Amortization Expense, Year Five	$ 21,724
Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Weighted Average Useful Life	10 years	10 years
Gross carrying amount	$ 476,176	$ 498,319
Accumulated amortization	(247,206)	(215,263)
Intangible assets, net	$ 228,970	$ 283,056
Patented Technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Weighted Average Useful Life	5 years	5 years
Gross carrying amount	$ 9,140	$ 13,154
Accumulated amortization	(4,435)	(7,894)
Intangible assets, net	4,705	5,260
Other Intangible Assets [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross carrying amount	6,721	917	[1]
Accumulated amortization	(4,514)	(907)	[1]
Intangible assets, net	2,207	$ 10	[1]
Acquired Finite-lived Intangible Asset, Useful Life, Minimum | Years		2
Acquired Finite-lived Intangible Asset, Useful Life, Maximum | Years		3
Trade Names [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross carrying amount	101,000	$ 101,000
Accumulated amortization	0	0
Intangible assets, net	$ 101,000	$ 101,000

[1] Consists of non-competition agreements with useful lives ranging from two to three years.