Consolidated Statements of Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Held-to-Maturity: Fair Value	$ 3,711,149	$ 3,894,121
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	58,051,646	57,959,074
Common Stock, outstanding shares	42,314,414	42,401,443
Treasury Stock, Shares	15,737,232	15,557,631