Accumulated Other Comprehensive Income or Loss and Earnings Per Share (Computation Of Basic And Diluted Earnings Per Common Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Equity [Abstract]
Net income	$ 154,750	$ 94,513	$ 334,948	$ 221,904
Less: Preferred stock dividends	6,991	6,991	13,982	13,982
Net income applicable to common shares	$ 147,759	$ 87,522	$ 320,966	$ 207,922
Weighted average common shares outstanding (in shares)	61,192	58,063	61,072	57,632
Effect of dilutive potential common shares
Common stock equivalents (in shares)	902	775	933	823
Weighted average common shares and effect of dilutive potential common shares (in shares)	62,094	58,838	62,005	58,455
Net income per common share:
Basic (usd per share)	$ 2.41	$ 1.51	$ 5.26	$ 3.61
Diluted (usd per share)	$ 2.38	$ 1.49	$ 5.18	$ 3.56