Consolidated Statements of Financial Condition (Parenthetical) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Securities available-for-sale, encumbered	$ 12,192,000	$ 29,902,000
Securities held-to-maturity, net estimated fair value	598,119,000	397,763,000
Securities held-to-maturity, net encumbered	$ 492,147,000	$ 371,270,000
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	32,136,892	17,286,557
Treasury stock, shares	1,429,880	16,280,215