CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Held to maturity, Fair Value	$ 74,748	$ 75,075
Preferred stock, par value
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value
Common stock, shares authorized	499,000,000	499,000,000
Common stock, shares issued	54,138,910	54,138,910
Common stock, shares outstanding	48,852,688	49,128,875
Treasury stock, shares	5,286,222	5,010,035