Income Per Share (Summary Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Per Share [Abstract]
Net income available to common stockholders	$ 41,510	$ 47,077	$ 75,696	$ 89,734
Weighted average shares outstanding-basic	133,802,622	128,419,745	131,183,857	127,437,970
Stock options	45,278	68,146	43,023	69,304
Unvested incentive units	74,345	135,185	65,847	120,222
2014 market performance-based awards	55,640		27,820
Weighted average shares/units outstanding-diluted	133,977,885	128,623,076	131,320,547	127,627,496
Basic	$ 0.31	$ 0.37	$ 0.58	$ 0.70
Diluted	$ 0.31	$ 0.37	$ 0.58	$ 0.70