Consolidated Statements of Financial Condition (Parenthetical) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Securities available-for-sale, encumbered	$ 5,339,000	$ 21,646,000
Allowance for credit loss	1,715,000	0
Securities held-to-maturity, net estimated fair value	968,466,000	777,290,000
Securities held-to-maturity, net encumbered	418,719,000	452,212,000
Loan receivable, allowance for credit losses	$ 60,735,000	$ 16,852,000
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)	57,370	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)	61,040,894	61,040,894
Common stock, shares outstanding (shares)	60,392,043	50,405,048
Treasury stock, shares (shares)	648,851	1,586,808