Interim Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Shares to be Issued for Deferred Compensation Obligations	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balances at Dec. 31, 2014	$ 174,594	$ 138,755	$ 4,242	$ 32,103	$ (506)
Beginning balances, shares at Dec. 31, 2014		7,776,274
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	6,406			7,771	(1,365)
Issuance of common stock	2,192	$ 2,192
Issuance of common stock, shares		94,807
Common stock transferred from the Rabbi Trust to satisfy deferred compensation obligations	0	$ 123	(123)
Share based payment awards under equity compensation plan	259		259
Common stock purchased for deferred compensation obligations	(165)	(165)
Common stock repurchased pursuant to publicly announced repurchase plan	(1,704)	$ (1,704)
Common stock repurchased pursuant to publicly announced repurchase plan, shares		(73,893)
Cash dividends	(3,557)			(3,557)
Ending balances at Jun. 30, 2015	178,025	$ 139,201	4,378	36,317	(1,871)
Ending balances, shares at Jun. 30, 2015		7,797,188
Beginning balances at Dec. 31, 2015	$ 183,971	$ 139,198	4,592	39,960	221
Beginning balances, shares at Dec. 31, 2015	7,799,867	7,799,867
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	$ 13,770			6,424	7,346
Issuance of common stock	2,489	$ 2,489
Issuance of common stock, shares		88,486
Common stock transferred from the Rabbi Trust to satisfy deferred compensation obligations	0	$ 127	(127)
Share based payment awards under equity compensation plan	273		273
Common stock purchased for deferred compensation obligations	(164)	(164)
Common stock repurchased pursuant to publicly announced repurchase plan	(1,462)	$ (1,462)
Common stock repurchased pursuant to publicly announced repurchase plan, shares		(51,911)
Cash dividends	(3,744)			(3,744)
Ending balances at Jun. 30, 2016	$ 195,133	$ 140,188	$ 4,738	$ 42,640	$ 7,567
Ending balances, shares at Jun. 30, 2016	7,836,442	7,836,442