Quarterly Financial Data Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2010
Quarterly Financial Data [Line Items]
Revenues	$ 528,104	$ 514,517	$ 486,511	$ 431,403	$ 394,255	$ 390,681	$ 329,885	$ 295,167	$ 281,171	$ 372,624	$ 1,960,535	$ 1,409,988	$ 1,522,817
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	145,594	200,649	216,731	181,242	170,115	177,446	144,021	130,236	129,266	90,636	744,216	621,818	353,439
Net Income (Loss) Attributable to Parent	$ 90,604	$ 123,948	$ 136,295	$ 112,279	$ 103,664	$ 108,807	$ 95,818	$ 77,238	$ 74,633	$ 51,300	$ 463,126	$ 385,527	$ 220,546
Earnings Per Share, Basic										$ 0.38			$ 1.65
Earnings Per Share, Diluted										$ 0.37			$ 1.60
Weighted Average Number of Shares Outstanding, Diluted										140,302,755			138,179,945