Condensed Consolidated Statements of Changes in Shareholders’ Equity (Unaudited) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balance at Dec. 31, 2016	$ 230	$ 278,501	$ 95,274	$ (15,446)	$ (922)	$ 357,637
Beginning balance, shares at Dec. 31, 2016	22,971,504			(909,432)
Net income			25,614			25,614
Dividends on common stock, $0.15 per share			(3,309)			(3,309)
Stock-based compensation expense		56				56
Exercise of stock options				$ 17		17
Exercise of stock options (in shares)				1,000
Other comprehensive income (loss), net of tax					1,106	1,106
Ending balance at Sep. 30, 2017	$ 230	278,557	117,579	$ (15,429)	184	381,121
Ending balance, shares at Sep. 30, 2017	22,971,504			(908,432)
Beginning balance at Dec. 31, 2017	$ 257	343,249	118,353	$ (15,256)	(389)	446,214
Beginning balance, shares at Dec. 31, 2017	25,731,504			(898,272)
Net income			33,177			33,177
Dividends on common stock, $0.15 per share			(3,762)			(3,762)
Stock-based compensation expense		1,154				1,154
Exercise of stock options		(181)		$ 431		250
Exercise of stock options (in shares)				25,400
Other comprehensive income (loss), net of tax					(5,182)	(5,182)
Ending balance at Sep. 30, 2018	$ 257	$ 344,222	$ 147,768	$ (14,825)	$ (5,571)	$ 471,851
Ending balance, shares at Sep. 30, 2018	25,731,504			(872,872)