Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands		Common Stock [Member]		Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2016		13,373,000
Balance at Dec. 31, 2016		$ 24,547		$ 70,218	$ (659)	$ 94,106
Net income				7,344		7,344
Other comprehensive income (loss), net of tax					393	393
Comprehensive income						7,737
Dividend on common stock				(1,862)		(1,862)
Stock issued pursuant to public offering, net of underwriting discounts and expenses of $1.7 million (in shares)		2,738,000
Stock issued pursuant to public offering, net of underwriting discounts and expenses of $1.7 million		$ 26,778				26,778
Stock compensation grants (in shares)		4,000
Stock compensation grants		$ 41				41
Common stock issued under employee plans (in shares)		30,000
Stock options exercised (in shares)		52,000
Stock options exercised		$ 245				245
Compensation expense associated with stock options		23				23
Compensation expense associated with restricted stock, net of cash paid when directly withholding shares for tax withholding purposes		$ 196				$ 196
Balance (in shares) at Dec. 31, 2017		16,197,000	[1]			16,271,563
Balance at Dec. 31, 2017	[1]	$ 51,830		75,700	(266)	$ 127,264
Net income				10,891		10,891
Other comprehensive income (loss), net of tax					(3,761)	(3,761)
Comprehensive income						7,130
Dividend on common stock				(1,786)		(1,786)
Stock compensation grants (in shares)		5,000
Stock compensation grants		$ 45				45
Common stock issued under employee plans (in shares)		23,000
Stock options exercised (in shares)		34,000
Stock options exercised		$ 197				197
Compensation expense associated with stock options		8				8
Compensation expense associated with restricted stock, net of cash paid when directly withholding shares for tax withholding purposes		$ 111				$ 111
Reclassification of accumulated other comprehensive income due to tax rate change				52	(52)
Balance (in shares) at Sep. 30, 2018		16,259,000	[2]			16,329,902
Balance at Sep. 30, 2018	[2]	$ 52,191		$ 84,857	$ (4,079)	$ 132,969

[1] Excludes 71 unvested restricted shares

[2] Excludes 71 unvested restricted shares