Shareholders' Equity 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
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Net income	$ 127,391	$ 153,148
Less: Preferred stock dividends	6,991	6,991
Net income applicable to common shares	$ 120,400	$ 146,157
Weighted average common shares outstanding (in shares)	57,196	56,904
Dilutive potential common shares (in shares)	862	681
Weighted average common shares and effect of dilutive potential common shares (in shares)	58,058	57,585
Net income per common share:
Basic (usd per share)	$ 2.11	$ 2.57
Diluted (usd per share)	$ 2.07	$ 2.54