Consolidated Condensed Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019		Dec. 31, 2018
Held-to-maturity, fair value (in dollars)	$ 523	[1]	$ 526
Loans receivable, allowance (in dollars)	$ 28,164		$ 28,331
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Common stock, shares authorized	50,000,000		50,000,000
Common stock, shares issued	25,373,619		25,398,992
Common stock, shares outstanding	19,713,192		20,171,392
Accumulated other comprehensive income, tax effect (in dollars)	$ 417		$ (468)
Treasury stock, shares	5,660,427		5,227,600
Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Preferred stock, shares authorized	4,963,000		4,963,000
Preferred stock, shares issued	0		0
Cumulative Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Preferred stock, shares authorized	37,000		37,000
Preferred stock, shares issued	0		0

[1] FHLMC, FNMA, and GNMA certificates are residential mortgage-backed securities.