Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Thousands		Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2017		$ 373,286	$ 0	$ 127	$ 160,940	$ 217	$ 262,900	$ (50,898)
Balance (in shares) at Dec. 31, 2017	[1]			20,312,082
Net income		11,737					11,737
Other comprehensive income (loss)		(2,810)				(2,810)
Adoption of ASU 2018-02 – See Note 2		0				47	(47)
Stock based compensation expenses		84			84
Shares issued under stock option plan, net		56			(33)		(36)	125
Shares issued under stock option plan, net (in shares)	[1]			11,276
Restricted share activity under stock incentive plans net		(113)			(458)		(81)	426
Restricted share activity under stock incentive plans net (in shares)	[1]			39,696
Shares issued from direct stock sales		21			14			7
Shares issued from direct stock sales (in shares)	[1]			744
Common stock dividends declared		(3,047)					(3,047)
Balance at Mar. 31, 2018		379,214	0	$ 127	160,547	(2,546)	271,426	(50,340)
Balance (in shares) at Mar. 31, 2018	[1]			20,363,798
Balance at Dec. 31, 2018		399,589	0	$ 127	161,593	(2,148)	295,588	(55,571)
Balance (in shares) at Dec. 31, 2018	[1]			20,171,392
Net income		11,482					11,482
Other comprehensive income (loss)		3,717				3,717
Deferred compensation plan		20			(22)			42
Stock based compensation expenses		11			11
Shares issued under stock option plan, net		185			(22)		(5)	212
Shares issued under stock option plan, net (in shares)	[1]			17,822
Restricted share activity under stock incentive plans net		(311)			(751)			440
Restricted share activity under stock incentive plans net (in shares)	[1]			38,890
Shares issued from direct stock sales		31			19			12
Shares issued from direct stock sales (in shares)	[1]			1,065
Shares repurchased		(15,147)						(15,147)
Shares repurchased (in shares)	[1]			(515,977)
Common stock dividends declared		(3,788)					(3,788)
Balance at Mar. 31, 2019		$ 395,789	$ 0	$ 127	$ 160,828	$ 1,569	$ 303,277	$ (70,012)
Balance (in shares) at Mar. 31, 2019	[1]			19,713,192

[1] Share data has been adjusted to reflect a 2-for-1 stock split on July 12, 2018