Consolidated Statements Of Condition (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Held-to-maturity securities, at Fair value	$ 851,842	$ 812,516	$ 787,489
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000	20,000,000
Common stock, $1.00 stated value (usd per share)	$ 1.00	$ 1.00	$ 1.00
Common stock, 100,000,000 shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	56,436,564	56,068,220	55,801,665
Treasury stock, (in shares)	107,288	103,013	101,738
Series D Preferred Stock
Preferred stock, liquidation value per share (usd per share)	$ 25	$ 25	$ 25
Preferred stock, shares outstanding (in shares)	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	5,000,000	5,000,000	5,000,000