Consolidated Statements of Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Held-to-Maturity: Fair Value	$ 3,960,956	$ 3,827,527
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, authorized shares	500,000,000	500,000,000
Common Stock, issued shares	57,958,200	57,856,672
Common Stock, outstanding shares	42,513,348	42,635,978
Treasury Stock, Shares	15,444,852	15,220,694