Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Loans receivable, allowance for loan losses	$ 38,156	$ 38,156	$ 33,639
Preferred stock, par value per share	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000	10,000,000
Preferred stock, shares issued	2,596	2,596	2,596
Preferred stock, shares outstanding	2,596	2,596	2,596
Common stock, no par value	$ 0	$ 0	$ 0
Common stock, shares authorized	40,000,000	40,000,000	40,000,000
Common stock, shares issued	19,692,259	19,692,259	19,574,858
Common stock, shares outstanding	17,035,675	17,035,675	17,107,640
Treasury stock, shares	2,656,584	2,656,584	2,467,218
Series D Preferred Stock [Member]
Preferred stock, dividend rate	4.50%	4.50%	4.50%
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000	$ 10,000
Series G Preferred Stock [Member]
Preferred stock, dividend rate	6.00%	6.00%	6.00%
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000	$ 10,000
Series H Preferred Stock [Member]
Preferred stock, dividend rate	3.50%	3.50%	3.50%
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000	$ 10,000