Consolidated Statements Of Condition (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Allowance for held-to-maturity securities losses	$ 99	$ 59	$ 70
Held-to-maturity securities, fair value	$ 2,121,065	$ 593,767	$ 879,192
Preferred stock, authorized (in shares)	20,000,000	20,000,000	20,000,000
Common stock, stated value (usd per share)	$ 1.00	$ 1.00	$ 1.00
Common stock, authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, issued (in shares)	58,726,900	58,473,252	58,266,136
Treasury stock (in shares)	1,703,627	1,703,627	720,784
Series D Preferred Stock
Preferred stock, liquidation value per share (usd per share)	$ 25	$ 25	$ 25
Preferred stock, issued (in shares)	5,000,000	5,000,000	5,000,000
Preferred stock, outstanding (in shares)	5,000,000	5,000,000	5,000,000
Series E Preferred Stock
Preferred stock, liquidation value per share (usd per share)	$ 25,000	$ 25,000	$ 25,000
Preferred stock, issued (in shares)	11,500	0	0
Preferred stock, outstanding (in shares)	11,500	0	0