Condensed Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	3,000,000	3,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	113,914,902	113,914,902
Common stock, shares outstanding (in shares)	97,603,151	97,456,478
Treasury stock, shares (in shares)	16,311,751	16,458,424
Securities held to maturity, fair value	$ 399,528	$ 418,249