Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) - USD ($) $ in Thousands	Total	Previously Reported	Common Stock	Common Stock Previously Reported	Additional Paid-in Capital	Additional Paid-in Capital Previously Reported	Treasury Stock	Treasury Stock Previously Reported	Retained Earnings	Retained Earnings Previously Reported	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Previously Reported
Balance at beginning of period at Dec. 31, 2016	$ 54,073		$ 2,818		$ 27,900		$ (2,114)		$ 29,960		$ (4,491)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,997								1,997
Other comprehensive income (loss)	372										372
Stock compensation expense	110				110
Exercise of stock options (48,586 shares), including tax benefit	1,263				1,263
Cash dividends declared on common stock	(1,168)								(1,168)
Balance at end of period at Jun. 30, 2017	56,647		2,818		29,273		(2,114)		30,789		(4,119)
Balance at beginning of period at Mar. 31, 2017											(4,233)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,041
Balance at end of period at Jun. 30, 2017	56,647		2,818		29,273		(2,114)		30,789		(4,119)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle for marketable equity securities, net of tax											(187)
Cumulative effect of change in accounting principle for marketable equity securities, net of tax | Accounting Standards Update 2016-01	0								187		(187)
Balance at beginning of period at Dec. 31, 2017	59,091	$ 59,091	2,966	$ 2,966	31,031	$ 31,031	(2,114)	$ (2,114)	32,913	$ 32,726	(5,705)	$ (5,518)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,775								2,775
Other comprehensive income (loss)	(1,251)										(1,251)
Stock compensation expense	150				150
Cash dividends declared on common stock	(1,272)								(1,272)
Balance at end of period at Jun. 30, 2018	59,493		2,966		31,181		(2,114)		34,416		(6,956)
Balance at beginning of period at Mar. 31, 2018											(6,720)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,413
Balance at end of period at Jun. 30, 2018	$ 59,493		$ 2,966		$ 31,181		$ (2,114)		$ 34,416		$ (6,956)