Investment 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	$ 1,649,160	$ 1,583,640	$ 4,876,269	$ 4,609,461
Operating expenses	1,230,366	1,130,717	3,554,598	3,270,185
Operating income	418,794	452,923	1,321,671	1,339,276
Other income, net	4,752	656	7,178	1,877
Net income	$ 423,546	$ 453,579	$ 1,328,849	$ 1,341,153