CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Less: ESOP Owned Shares [Member]	Total
Balance at Dec. 31, 2017	$ 15,154	$ 85,888	$ 120,589	$ (446)	$ (5,858)	$ (57,121)	$ 158,206
Balance (in shares) at Dec. 31, 2017	15,153,510
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	23,427	0	0	0	23,427
Cash dividends, common	0	0	(17,544)	0	0	0	(17,544)
Other comprehensive income (loss), (net of tax)	0	0	0	(5,042)	0	0	(5,042)
Balance at Sep. 30, 2018	$ 15,154	85,888	126,472	(5,488)	(5,858)	(57,121)	159,047
Balance (in shares) at Sep. 30, 2018	15,153,510
Balance at Jun. 30, 2018	$ 15,154	85,888	121,559	(3,647)	(5,858)	(57,121)	155,975
Balance (in shares) at Jun. 30, 2018	15,153,510
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	4,913	0	0	0	4,913
Other comprehensive income (loss), (net of tax)	0	0	0	(1,841)	0	0	(1,841)
Balance at Sep. 30, 2018	$ 15,154	85,888	126,472	(5,488)	(5,858)	(57,121)	159,047
Balance (in shares) at Sep. 30, 2018	15,153,510
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative change in accounting principle	$ 0	0	(1,279)	0	0	0	(1,279)
Balance at Dec. 31, 2018	$ 14,772	80,412	119,834	(2,243)	0	(58,195)	$ 154,580
Balance (in shares) at Dec. 31, 2018	14,771,520						14,771,520
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	$ 3,207	48,185	0	0	0	0	$ 51,392
Issuance of common stock, net (in shares)	3,207,000
Net income	$ 0	0	19,111	0	0	0	19,111
Cash dividends, common	0	0	(539)	0	0	0	(539)
Other comprehensive income (loss), (net of tax)	0	0	0	5,871	0	0	5,871
Terminated ESOP put option	0	0	0	0	0	58,195	58,195
Exercise of employee stock options, net of 63,100 shares for cashless exercise and net of 8,597 shares for taxes	$ 25	(186)	0	0	0	0	(161)
Exercise of employee stock options, net of 63,100 shares for cashless exercise and net of 8,597 shares for taxes (in shares)	25,803
Stock based compensation	$ 0	407	0	0	0	0	407
Share-based liability awards modified to equity awards	0	11,450	0	0	0	0	11,450
Balance at Sep. 30, 2019	$ 18,004	140,268	137,127	3,628	0	0	$ 299,027
Balance (in shares) at Sep. 30, 2019	18,004,323						18,004,323
Balance at Jun. 30, 2019	$ 17,979	140,189	129,408	3,537	0	0	$ 291,113
Balance (in shares) at Jun. 30, 2019	17,978,520
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	$ 0	0	0	0	0	0	0
Issuance of common stock, net (in shares)	0
Net income	$ 0	0	8,258	0	0	0	8,258
Cash dividends, common	0	0	(539)	0	0	0	(539)
Other comprehensive income (loss), (net of tax)	0	0	0	91	0	0	91
Terminated ESOP put option	0	0	0	0	0		0
Exercise of employee stock options, net of 63,100 shares for cashless exercise and net of 8,597 shares for taxes	$ 25	(186)	0	0	0	0	(161)
Exercise of employee stock options, net of 63,100 shares for cashless exercise and net of 8,597 shares for taxes (in shares)	25,803
Stock based compensation	$ 0	265	0	0	0	0	265
Share-based liability awards modified to equity awards	0	0	0	0	0	0	0
Balance at Sep. 30, 2019	$ 18,004	$ 140,268	$ 137,127	$ 3,628	$ 0	$ 0	$ 299,027
Balance (in shares) at Sep. 30, 2019	18,004,323						18,004,323