Business Segment and Geographic Area Information (Schedule of Revenues by Geographic Customer and Related Percentage of Total Revenues) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 452,033	$ 646,008
Revenues [Member] | United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	450,696	644,820
Percentage	99.70%	99.80%
Revenues [Member] | International [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 1,337	$ 1,188
Percentage	0.30%	0.20%