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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings for basic and diluted earnings per common share:
Net income	$ 53,097	$ 98,649	$ 91,296	$ 198,385
Less: Preferred stock dividends	1,969	1,969	3,938	3,938
Undistributed Earnings, Basic	51,128	96,680	87,358	194,447
Undistributed Earnings, Diluted, Total	51,128	96,680	87,358	194,447
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	399	487	592	964
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	399	487	592	964
Earnings applicable to common shareholders	50,729	96,193	86,766	193,483
Earnings applicable to common shareholders	$ 50,729	$ 96,193	$ 86,766	$ 193,483
Shares:
Weighted-average common shares outstanding - basic	89,485	91,534	90,206	91,550
Effect of dilutive securities	85	321	185	348
Weighted-average common shares outstanding - diluted	89,570	91,855	90,391	91,898
Earnings per common share(1):
Basic	$ 0.57	$ 1.05	$ 0.96	$ 2.11
Diluted	$ 0.57	$ 1.05	$ 0.96	$ 2.11