Earnings Per Share (Schedule Of Net Income Attributable To Common Stockholders) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]
Net income	$ 170,972	$ 170,290	$ 145,816	$ 123,347	$ 95,277	$ 86,964	$ 115,501	$ 87,813	$ 610,425	$ 385,555	$ 258,966
Less: Net income attributable to participating securities									(2,562)	(2,160)	(2,310)
Net income attributable to common shareholders									$ 607,863	$ 383,395	$ 256,656