Segment Reporting (Revenue by Geographical Areas) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues from External Customers [Line Items]
Revenues	$ 468,618	$ 407,864	$ 907,892	$ 786,908
Domestic [Member]
Revenues from External Customers [Line Items]
Revenues	448,296	388,744	866,960	747,393
Foreign [Member]
Revenues from External Customers [Line Items]
Revenues	$ 20,322	$ 19,120	$ 40,932	$ 39,515