Investments in Unconsolidated Entities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Equity method investments, combined income statements
Revenues	$ 1,733,402	$ 1,643,734	$ 5,184,186	$ 4,861,057
Operating expenses	1,263,320	1,225,417	3,826,798	3,540,783
Operating income	470,082	418,317	1,357,388	1,320,274
Other income (loss), net	(9,843)	1,651	(15,466)	4,077
Net income	$ 460,239	$ 419,968	$ 1,341,922	$ 1,324,351