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
	Mar. 31, 2013	Mar. 31, 2012
Shareholders' Equity and Earnings Per Share Disclosure [Abstract]
Net income	$ 32,052	$ 23,210
Less: Preferred stock dividends and discount accretion	2,616	1,246
Net income applicable to common shares	29,436	21,964
Add: Dividends on convertible preferred stock, if dilutive	2,581	0
Net income applicable to common shares-Diluted	$ 32,017	$ 21,964
Weighted average common shares outstanding	36,976	36,207
Effect of dilutive potential common shares
Common stock equivalents	7,443	7,530
Convertible preferred stock, if dilutive	5,020	0
Effect of dilutive potential common shares	12,463	7,530
Weighted average common shares and effect of dilutive potential common shares	49,439	43,737
Net income per common share - Basic	$ 0.80	$ 0.61
Net income per common share - Diluted	$ 0.65	$ 0.50