Segment Reporting (Revenue by Geographical Areas) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues from External Customers [Line Items]
Revenues	$ 608,088	$ 485,323	$ 1,190,128	$ 915,368
Revenue as Percentage of Consolidated Revenue	100.00%	100.00%	100.00%	100.00%
Domestic [Member]
Revenues from External Customers [Line Items]
Revenues	$ 578,165	$ 462,989	$ 1,132,603	$ 873,745
Revenue as Percentage of Consolidated Revenue	95.10%	95.40%	95.20%	95.50%
Foreign [Member]
Revenues from External Customers [Line Items]
Revenues	$ 29,923	$ 22,334	$ 57,525	$ 41,623
Revenue as Percentage of Consolidated Revenue	4.90%	4.60%	4.80%	4.50%