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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings for basic and diluted earnings per common share:
Net income	$ 94,035	$ 53,097	$ 202,113	$ 91,296
Less: Preferred stock dividends	1,969	1,969	3,938	3,938
Undistributed Earnings, Basic	92,066	51,128	198,175	87,358
Undistributed Earnings, Diluted, Total	92,066	51,128	198,175	87,358
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	511	399	1,090	592
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	511	399	1,090	592
Earnings applicable to common shareholders	91,555	50,729	197,085	86,766
Earnings applicable to common shareholders	$ 91,555	$ 50,729	$ 197,085	$ 86,766
Shares:
Weighted-average common shares outstanding - basic	90,027	89,485	89,918	90,206
Effect of dilutive securities	194	85	246	185
Weighted-average common shares outstanding - diluted	90,221	89,570	90,164	90,391
Earnings per common share (1):
Basic	$ 1.02	$ 0.57	$ 2.19	$ 0.96
Diluted	$ 1.01	$ 0.57	$ 2.19	$ 0.96