CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balance at Dec. 31, 2015	$ 230	$ 281,163	$ 72,462	$ (10,955)	$ 1,414	$ 344,314
Beginning balance, shares at Dec. 31, 2015	22,971,504			(668,030)
Purchase of Shares of Treasury Stock				$ (11,079)		(11,079)
Purchase of Shares of Treasury Stock, Shares				(635,100)
Issuance of Shares of Treasury Stock by Exercise of Stock Options		(1,336)		$ 3,333		1,997
Issuance of Shares of Treasury Stock by Exercise of Stock Options, Shares				202,044
Stock‑based Compensation Expense		35				35
Dividends on Common Stock			(3,293)			(3,293)
Net income			19,651			19,651
Other comprehensive income, net of tax					893	893
Ending balance at Sep. 30, 2016	$ 230	279,862	88,820	$ (18,701)	2,307	352,518
Ending balance, shares at Sep. 30, 2016	22,971,504			(1,101,086)
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)
Issuance of Shares of Treasury Stock by Exercise of Stock Options				$ 17		17
Issuance of Shares of Treasury Stock by Exercise of Stock Options, Shares				1,000
Stock‑based Compensation Expense		56				56
Dividends on Common Stock			(3,309)			(3,309)
Net income			25,614			25,614
Other comprehensive income, 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)