Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Unearned ESOP Shares	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2018	$ 97	$ 65,090	$ (4,893)	$ 182,594	$ (7,809)	$ 235,079
Balance (in shares) at Dec. 31, 2018	9,645,955
Increase (Decrease) in Stockholders' Equity
Net income				11,584		11,584
Other comprehensive income (loss)					609	609
Adoption of lease accounting standard				(10)		(10)
Cash dividends declared				(4,979)		(4,979)
Share-based compensation		371				371
Share-based compensation (in shares)	6,541
Allocation of ESOP shares		434	244			678
Repurchase of shares of common stock	$ (2)	(4,721)				(4,723)
Repurchase of shares of common stock (in shares)	(169,873)
Exercise of options for common stock	$ 2	3,161				3,163
Exercise of options for common stock (in shares)	182,170
Balance at Jun. 30, 2019	$ 97	64,335	(4,649)	189,189	(7,200)	241,772
Balance (in shares) at Jun. 30, 2019	9,664,793
Balance at Mar. 31, 2019	$ 96	63,748	(4,771)	187,084	(7,319)	238,838
Balance (in shares) at Mar. 31, 2019	9,616,195
Increase (Decrease) in Stockholders' Equity
Net income				5,060		5,060
Other comprehensive income (loss)					119	119
Cash dividends declared				(2,955)		(2,955)
Share-based compensation		285				285
Share-based compensation (in shares)	3,201
Allocation of ESOP shares		223	122			345
Repurchase of shares of common stock	$ (1)	(1,788)				(1,789)
Repurchase of shares of common stock (in shares)	(62,213)
Exercise of options for common stock	$ 2	1,867				1,869
Exercise of options for common stock (in shares)	107,610
Balance at Jun. 30, 2019	$ 97	64,335	(4,649)	189,189	(7,200)	241,772
Balance (in shares) at Jun. 30, 2019	9,664,793
Balance at Dec. 31, 2019	$ 97	65,057	(4,404)	190,808	(7,668)	243,890
Balance (in shares) at Dec. 31, 2019	9,681,493
Increase (Decrease) in Stockholders' Equity
Net income				8,764		8,764
Other comprehensive income (loss)					(195)	(195)
Cash dividends declared				(4,224)		(4,224)
Share-based compensation		366				366
Share-based compensation (in shares)	18,875
Allocation of ESOP shares		396	245			641
Repurchase of shares of common stock	$ (3)	(6,633)				(6,636)
Repurchase of shares of common stock (in shares)	(268,328)
Exercise of options for common stock	$ 1	1,420				1,421
Exercise of options for common stock (in shares)	81,827
Balance at Jun. 30, 2020	$ 95	60,606	(4,159)	195,348	(7,863)	244,027
Balance (in shares) at Jun. 30, 2020	9,513,867
Balance at Mar. 31, 2020	$ 96	62,715	(4,282)	193,160	(7,770)	243,919
Balance (in shares) at Mar. 31, 2020	9,593,332
Increase (Decrease) in Stockholders' Equity
Net income				4,291		4,291
Other comprehensive income (loss)					(93)	(93)
Cash dividends declared				(2,103)		(2,103)
Share-based compensation		209				209
Share-based compensation (in shares)	3,204
Allocation of ESOP shares		179	123			302
Repurchase of shares of common stock	$ (2)	(3,526)				(3,528)
Repurchase of shares of common stock (in shares)	(141,949)
Exercise of options for common stock	$ 1	1,029				1,030
Exercise of options for common stock (in shares)	59,280
Balance at Jun. 30, 2020	$ 95	$ 60,606	$ (4,159)	$ 195,348	$ (7,863)	$ 244,027
Balance (in shares) at Jun. 30, 2020	9,513,867