Segment Information (Schedule of Revenue by Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues, net	$ 726,934	$ 648,023	$ 710,545	$ 720,189	$ 729,597	$ 634,646	$ 684,832	$ 706,579	$ 2,805,691	$ 2,755,654	$ 2,580,935
North America [Member]
Segment Reporting Information [Line Items]
Revenues, net									2,244,057	2,215,430
Europe [Member]
Segment Reporting Information [Line Items]
Revenues, net									369,815	384,234
Other Geographic Locations [Member]
Segment Reporting Information [Line Items]
Revenues, net									$ 191,819	$ 155,990