Segments and Operations by Geographic Area (Foreign Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,269,385	$ 1,067,300	$ 3,165,657	$ 2,794,431
Property and equipment, net	504,313		504,313		350,192
Goodwill and other intangible assets, net	1,064,099		1,064,099		961,973
Continuing Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,269,400	1,067,300	3,165,700	2,794,400
Discontinued Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	4,800	4,800	18,000	73,700
Reportable Geographical Components [Member] | Foreign Operations [Member] | Continuing Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	90,900	33,700	172,000	133,700
Property and equipment, net	48,800		48,800		11,400
Goodwill and other intangible assets, net	94,000		94,000		30,500
Reportable Geographical Components [Member] | Foreign Operations [Member] | Discontinued Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,300	1,900	7,000	4,600
Reportable Geographical Components [Member] | UNITED STATES | Continuing Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,178,500	1,033,600	2,993,700	2,660,700
Reportable Geographical Components [Member] | UNITED STATES | Discontinued Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 2,500	$ 2,900	$ 11,000	$ 69,100