Consolidated Statements of Financial Condition (Parenthetical) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Securities available-for-sale, encumbered	$ 21,646,000	$ 26,509,000
Securities held-to-maturity, net estimated fair value	777,290,000	832,815,000
Securities held-to-maturity, net encumbered	$ 452,212,000	$ 550,735,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 1,000	$ 1,000
Preferred stock, shares authorized (shares)	5,000,000	5,000,000
Preferred stock, shares issued (shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	51,991,856	51,991,856
Common stock, shares outstanding (shares)	50,405,048	47,951,168
Treasury stock, shares (shares)	1,586,808	459,251