Shareholders' Equity And Earnings Per Share (Computation Of Basic And Diluted Earnings Per Common Share) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Shareholders' Equity and Earnings Per Share Disclosure [Abstract]
Net income	$ 34,307	$ 25,595	$ 66,359	$ 48,805
Less: Preferred stock dividends and discount accretion	2,617	2,644	5,233	3,890
Net income applicable to common shares	31,690	22,951	61,126	44,915
Add: Dividends on convertible preferred stock, if dilutive	2,581	0	5,162	0
Net income applicable to common shares-Diluted	$ 34,271	$ 22,951	$ 66,288	$ 44,915
Weighted average common shares outstanding	37,486	36,329	37,231	36,266
Effect of dilutive potential common shares
Common stock equivalents	7,334	7,770	7,343	7,723
Convertible preferred stock, if dilutive	5,020	0	5,020	0
Total dilutive potential common shares	12,354	7,770	12,363	7,723
Weighted average common shares and effect of dilutive potential common shares	49,840	44,099	49,594	43,989
Net income per common share - Basic (in usd per share)	$ 0.85	$ 0.63	$ 1.64	$ 1.24
Net income per common share - Diluted (in usd per share)	$ 0.69	$ 0.52	$ 1.34	$ 1.02