Segments and Operations by Geographic Area (Foreign Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 977,624	$ 988,874	$ 1,896,272	$ 1,727,131
Property and equipment, net	470,544		470,544		350,378
Goodwill and other intangible assets, net	1,028,908	823,300	1,028,908	823,300	963,210	825,500
Segment, Continuing Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	977,600	988,900	1,896,300	1,727,100
Segment, Discontinued Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	6,900	28,700	13,200	68,900
Reportable Geographical Components [Member] | Foreign Operation [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	49,500		49,500		12,900
Reportable Geographical Components [Member] | Foreign Operation [Member] | Segment, Continuing Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	41,400	37,700	81,200	100,000
Property and equipment, net	47,900		47,900		11,400
Goodwill and other intangible assets, net	91,800		91,800		30,500
Reportable Geographical Components [Member] | Foreign Operation [Member] | Segment, Discontinued Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,400	1,000	4,700	2,700
Property and equipment, net	1,600		1,600		1,500
Reportable Geographical Components [Member] | UNITED STATES | Segment, Continuing Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	936,200	951,200	1,815,100	1,627,100
Reportable Geographical Components [Member] | UNITED STATES | Segment, Discontinued Operations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 4,500	$ 27,700	$ 8,500	$ 66,200