Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Stockholders' Equity, Total	SBLF Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance Beginning of Period at Dec. 31, 2014		$ 419,745	$ 57,943	$ 138	$ 22,345	$ 332,283	$ 7,036	$ 0
Net income (loss)	$ 46,502	46,502	0	0	0	46,502	0	0
Stock issued under Stock Option Plan		3,744	0	0	2,026	0	0	1,718
Common dividends declared		(11,896)	0	0	0	(11,896)	0	0
SBLF preferred stock dividends accrued (1.0%)		(553)	0	0	0	(553)	0	0
Other comprehensive loss	(1,372)	(1,372)	0	0	0	0	(1,372)	0
Reclassification of treasury stock per Maryland law		0	0	1	0	1,717	0	(1,718)
Redemption of SBLF preferred stock		(57,943)	(57,943)	0	0	0	0	0
Balance End of Period at Dec. 31, 2015		398,227	0	139	24,371	368,053	5,664	0
Net income (loss)	45,342	45,342	0	0	0	45,342	0	0
Stock issued under Stock Option Plan		2,593	0	0	1,571	0	0	1,022
Common dividends declared		(12,250)	0	0	0	(12,250)	0	0
Other comprehensive loss	(4,106)	(4,106)	0	0	0	0	(4,106)	0
Reclassification of treasury stock per Maryland law		0	0	1	0	1,021	0	(1,022)
Balance End of Period at Dec. 31, 2016		429,806	0	140	25,942	402,166	1,558	0
Net income (loss)	51,564	51,564	0	0	0	51,564	0	0
Stock issued under Stock Option Plan		3,811	0	0	2,261	0	0	1,550
Common dividends declared		(13,202)	0	0	0	(13,202)	0	0
Other comprehensive loss	$ (317)	(317)	0	0	0	0	(317)	0
Reclassification of treasury stock per Maryland law		0	0	1	0	1,549	0	(1,550)
Balance End of Period at Dec. 31, 2017		$ 471,662	$ 0	$ 141	$ 28,203	$ 442,077	$ 1,241	$ 0