Segment Information (Revenues by geographic region) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenues, net	$ 710,545	$ 684,832	$ 1,430,734	$ 1,391,411
United States
Segment Reporting Information [Line Items]
Revenues, net	548,555	542,803	1,148,610	1,117,137
Europe
Segment Reporting Information [Line Items]
Revenues, net	108,076	103,560	186,750	197,522
Other Geographic Locations
Segment Reporting Information [Line Items]
Revenues, net	$ 53,914	$ 38,469	$ 95,374	$ 76,752