CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)	Total
Balance at Dec. 31, 2014	$ 11,159	$ (8,701)	$ 246,635	$ 97,856	$ 13,713	$ 360,662
Balance (in shares) at Dec. 31, 2014	21,687,525
Increase (Decrease) in Shareholders' Equity
Net Income (Loss) Available to Common Stockholders, Basic				35,542		35,542
Other comprehensive income (loss)					(1,089)	(1,089)
Purchase of treasury stock		(3,527)				(3,527)
Purchase of treasury shares (in shares)	(176,405)
Stock option exercise	$ 13	416	(135)			294
Stock option exercise (in shares)	25,075
Stock option expense			180			180
Dividends - common stock				(11,680)		(11,680)
Restricted stock award	$ 21		642			663
Restricted stock award (in shares)	27,955
Director retainer award	$ 8		307			315
Director retainer award (in shares)	15,425
Balance at Dec. 31, 2015	$ 11,201	(11,812)	247,629	121,718	12,624	381,360
Balance (in shares) at Dec. 31, 2015	21,579,575
Increase (Decrease) in Shareholders' Equity
Net Income (Loss) Available to Common Stockholders, Basic				38,323		38,323
Other comprehensive income (loss)					(9,545)	(9,545)
Purchase of treasury stock		(1,045)				(1,045)
Purchase of treasury shares (in shares)	(39,888)
Stock option exercise	$ 55	1,948	(220)			1,783
Stock option exercise (in shares)	111,595
Stock option expense			91			91
Dividends - common stock				(14,296)		(14,296)
Restricted stock award	$ 22		1,032			1,054
Restricted stock award (in shares)	45,932
Director retainer award	$ 9		373			382
Director retainer award (in shares)	18,334
Issuance of common stock in acquisition	$ 1,176		50,211			51,387
Issuance of common stock in acquisition (in shares)	2,351,816
Balance at Dec. 31, 2016	$ 12,463	(10,909)	299,116	145,745	3,079	449,494
Balance (in shares) at Dec. 31, 2016	24,067,364
Increase (Decrease) in Shareholders' Equity
Net Income (Loss) Available to Common Stockholders, Basic				49,438		49,438
Other comprehensive income (loss)					1,124	1,124
Purchase of treasury stock		(395)				(395)
Purchase of treasury shares (in shares)	(11,775)
Stock option exercise	$ 46	1,627	(530)			1,143
Stock option exercise (in shares)	91,556
Stock option expense			28			28
Dividends - common stock				(17,162)		(17,162)
Restricted stock award	$ 33		975			1,008
Restricted stock award (in shares)	28,052
Director retainer award	$ 7		304			311
Director retainer award (in shares)	8,204
Issuance of common stock in acquisition	$ 701		47,268			47,969
Issuance of common stock in acquisition (in shares)	1,402,612
Balance at Dec. 31, 2017	$ 13,250	$ (9,677)	$ 347,161	$ 178,021	$ 4,203	$ 532,958
Balance (in shares) at Dec. 31, 2017	25,586,013