Earnings Per Common Share (Earnings Per Share Basic And Diluted) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings for basic and diluted earnings per common share:
Net income	$ 61,579	$ 50,603	$ 121,050	$ 97,650
Less: Preferred stock dividends	2,024	2,024	4,048	4,048
Undistributed Earnings, Basic	59,555	48,579	117,002	93,602
Net income available to common shareholders	59,555	48,579	117,002	93,602
Less: Earnings applicable to participating securities	70	181	176	320
Less: Earnings applicable to participating securities	70	181	176	320
Earnings applicable to common shareholders	59,485	48,398	116,826	93,282
Earnings applicable to common shareholders	$ 59,485	$ 48,398	$ 116,826	$ 93,282
Shares:
Weighted average common shares outstanding - basic (in shares)	92,092	91,244	91,989	91,247
Effect of dilutive securities:
Stock options and restricted stock (in shares)	397	475	475	453
Warrants (in shares)	6	26	6	26
Weighted-average common shares outstanding - diluted (in shares)	92,495	91,745	92,470	91,726
Earnings per common share:
Basic (in dollars per share)	$ 0.65	$ 0.53	$ 1.27	$ 1.02
Diluted (in dollars per share)	$ 0.64	$ 0.53	$ 1.26	$ 1.02