Investments in Unconsolidated Entities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Equity method investments, combined income statements
Revenues	$ 1,643,734	$ 1,577,934	$ 4,861,057	$ 4,593,690
Operating expenses	1,225,417	1,125,966	3,540,783	3,256,399
Operating income	418,317	451,968	1,320,274	1,337,291
Other income, net	1,651	1,063	4,077	2,773
Net income	$ 419,968	$ 453,031	$ 1,324,351	$ 1,340,064