Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Total
Beginning balance at Dec. 31, 2016		$ 21,382	$ 228,142	$ 170,377	$ (78,833)	$ (2,011)	$ 339,057
Net income				12,620			12,620
Other comprehensive income (loss)						2,010	2,010
Common dividends declared				(5,441)			(5,441)
Equity-based compensation expense			124		378		502
Common stock options exercised			(17)		64		47
Issuance of treasury stock to 401(k) plan -- 8,869 shares			77		159		236
Purchase of treasury shares					(256)		(256)
Ending balance at Jun. 30, 2017		21,382	228,326	177,556	(78,488)	(1)	348,775
Beginning balance at Mar. 31, 2017						(1,481)
Net income							6,418
Other comprehensive income (loss)						1,480	1,480
Ending balance at Jun. 30, 2017		21,382	228,326	177,556	(78,488)	(1)	348,775
Beginning balance at Dec. 31, 2017		21,382	228,750	180,543	(79,121)	(840)	350,714	[1]
Net income				17,934			17,934
Other comprehensive income (loss)						(1,745)	(1,745)
Common dividends declared				(6,064)			(6,064)
Equity-based compensation expense			151		594		745
Common stock options exercised			(38)		195		157
Issuance of treasury stock to 401(k) plan -- 8,869 shares			86		143		229
Purchase of treasury shares					(14,715)		(14,715)
Special common dividend declared -- $0.48 per share				(8,134)			(8,134)
Ending balance at Jun. 30, 2018		21,382	228,949	184,279	(92,904)	(2,585)	339,121
Beginning balance at Mar. 31, 2018						(2,481)
Net income							9,066
Other comprehensive income (loss)						(104)	(104)
Ending balance at Jun. 30, 2018		$ 21,382	$ 228,949	$ 184,279	$ (92,904)	$ (2,585)	$ 339,121

[1] Derived from audited financial statements