Earnings Per Share (Computation Of Basic And Diluted Earnings Per Common Share) (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, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share [Abstract]
Net income	$ 30,089	$ 32,302	$ 25,595	$ 23,210	$ 19,221	$ 30,202	$ 11,750	$ 16,402	$ 111,196	$ 77,575	$ 63,329
Less: Preferred stock dividends and discount accretion	2,616	2,616	2,644	1,246	1,032	1,032	1,033	1,031	9,093	4,128	19,643
Less: Non-cash deemed preferred stock dividend									0	0	11,361
Net income applicable to common shares	27,473	29,686	22,951	21,964	18,189	29,170	10,717	15,371	102,103	73,447	32,325
Add: Dividends on convertible preferred stock									8,955	0	0
Net income applicable to common shares - Diluted									$ 111,058	$ 73,447	$ 32,325
Weighted average common shares outstanding (in shares)									36,365	35,355	30,057
Effect of dilutive potential common shares - Common stock equivalents (in shares)									7,313	8,636	1,513
Effect of dilutive potential common shares - Convertible preferred stock, if dilutive (in shares)									4,356	0	0
Dilutive potential common shares (in shares)									11,669	8,636	1,513
Average common shares and dilutive common shares (in shares)									48,034	43,991	31,570
Net income per common share - Basic (in usd per share)	$ 0.75	$ 0.82	$ 0.63	$ 0.61	$ 0.51	$ 0.82	$ 0.31	$ 0.44	$ 2.81	$ 2.08	$ 1.08
Net income per common share - Diluted (in usd per share)	$ 0.61	$ 0.66	$ 0.52	$ 0.50	$ 0.41	$ 0.65	$ 0.25	$ 0.36	$ 2.31	$ 1.67	$ 1.02