Net Income Per Common Share (Schedule Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income	$ 105,070	$ 109,059	$ 111,181	$ 103,166	$ 29,605	$ 98,007	$ 76,003	$ 71,857	$ 428,476	$ 275,474	$ 246,784
Preferred stock dividends and redemption charge									17,998	10,238	10,238
Net income available to common shareholders	$ 101,919	$ 99,330	$ 108,622	$ 100,607	$ 27,046	$ 95,448	$ 73,444	$ 69,298	$ 410,478	$ 265,236	$ 236,546
Weighted average common shares outstanding									117,644	121,162	124,389
Potentially dilutive shares from outstanding equity-based awards and Earnout Payments									734	850	689
Weighted average diluted common shares									118,378	122,012	125,078
Net income per common share, basic (in dollars per share)	$ 0.88	$ 0.85	$ 0.92	$ 0.85	$ 0.23	$ 0.79	$ 0.60	$ 0.57	$ 3.49	$ 2.19	$ 1.90
Net income per common share, diluted (in dollars per share)	$ 0.87	$ 0.84	$ 0.91	$ 0.84	$ 0.23	$ 0.78	$ 0.60	$ 0.56	$ 3.47	$ 2.17	$ 1.89