Consolidated Statements of Financial Condition (Parenthetical) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Securities held-to-maturity, net estimated fair value	$ 420,409,000	$ 474,215,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 1,000	$ 1,000
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	55,000,000	55,000,000
Common stock, shares issued	33,566,772	33,566,772
Common stock, shares outstanding	16,722,632	16,901,653
Treasury stock, shares	16,844,140	16,665,119