Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2013	$ 167,551	$ 7,891	$ 58,050	$ 99,090	$ 2,520
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,741			12,741
Other comprehensive income (loss)	1,144				1,144
Stock repurchased	(1,508)	(70)	(1,438)
Stock options exercised	442	26	416
Equity-based compensation	647	25	622
Cash dividends paid	(7,237)			(7,237)
Ending Balance at Dec. 31, 2014	173,780	7,872	57,650	104,594	3,664
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,039			15,039
Other comprehensive income (loss)	(1,374)				(1,374)
Issuance of common stock	20,483	826	19,657
Stock repurchased	(3,506)	(151)	(3,355)
Stock options exercised	789	43	746
Equity-based compensation	692	15	677
Cash dividends paid	(8,068)			(8,068)
Ending Balance at Dec. 31, 2015	197,835	8,605	75,375	111,565	2,290
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,301			16,301
Other comprehensive income (loss)	(4,164)				(4,164)
Stock repurchased	(1,292)	(51)	(1,241)
Stock options exercised	142	6	136
Vesting of restricted stock		5	(5)
Equity-based compensation	824	13	811
Cash dividends paid	(8,266)			(8,266)
Ending Balance at Dec. 31, 2016	$ 201,380	$ 8,578	$ 75,076	$ 119,600	$ (1,874)