Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Investment securities held-to-maturity, fair value	$ 278,716	$ 256,771
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	400,000,000	400,000,000
Common Stock, shares issued	51,516,335	51,518,162
Common Stock, shares outstanding	30,479,969	26,875,585
Treasury stock, shares	20,814,584	24,479,020