Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member]	Preferred Stock Including Additional Paid in Capital [Member]	Common Stock [Member]	Common Stock Including Additional Paid in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2017			$ 2,966	$ 31,031	$ (2,114)	$ 32,726	$ (5,518)	$ 59,091
Cumulative effect of change in accounting principle for marketable equity securities, net of tax at Dec. 31, 2017						187	(187)
Balance, as adjusted at Dec. 31, 2017			2,966	31,031	(2,114)	32,913	(5,705)	59,091
Net income						1,362		1,362
Other comprehensive income (loss)							(1,015)	(1,015)
Stock compensation expense				75				75
Cash dividends declared on common stock						(636)		(636)
Balance at Mar. 31, 2018			2,966	31,106	(2,114)	33,639	(6,720)	58,877
Balance at Dec. 31, 2017			2,966	31,031	(2,114)	32,726	(5,518)	59,091
Cumulative effect of change in accounting principle for marketable equity securities, net of tax at Dec. 31, 2017						187	(187)
Balance, as adjusted at Dec. 31, 2017			2,966	31,031	(2,114)	32,913	(5,705)	59,091
Balance at Dec. 31, 2018	421	3,785	3,501	46,401	(2,114)	34,371	(6,357)	80,008
Cumulative effect of change in accounting principle for marketable equity securities, net of tax at Dec. 31, 2018						(181)		(181)
Balance, as adjusted at Dec. 31, 2018	421	3,785	3,501	46,401	(2,114)	34,190	(6,357)	79,827
Net income						2,082		2,082
Other comprehensive income (loss)							873	873
Stock compensation expense				90				90
Cash dividends declared on common stock						(783)		(783)
Balance at Mar. 31, 2019	$ 421	$ 3,785	$ 3,501	$ 46,491	$ (2,114)	$ 35,489	$ (5,484)	$ 82,089