Consolidated Statements of Changes in Shareholders' Equity - Unaudited - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance, preferred stock (shares) at Dec. 31, 2014		0
Beginning balance, common stock (shares) at Dec. 31, 2014			26,745,529
Beginning balance at Dec. 31, 2014	$ 443,145	$ 0	$ 27,278	$ 355,822	$ 68,421	$ (122)	$ (8,254)
Net income	25,508				25,508
Other comprehensive income (loss)	(3,992)					(3,992)
Issuance of stock, net of offering costs (shares)		2,300,000
Issuance of stock, net of offering costs	55,569	$ 55,569
Preferred stock dividends	(507)				(507)
Share-based compensation expense	2,359			2,359
Issuance of common stock under share-based compensation arrangements (shares)			126,216
Issuance of common stock under share-based compensation arrangements	1,419		$ 124	1,274			21
Ending balance, preferred stock (shares) at Jun. 30, 2015		2,300,000
Ending balance, common stock (shares) at Jun. 30, 2015			26,871,745
Ending balance at Jun. 30, 2015	523,501	$ 55,569	$ 27,402	359,455	93,422	(4,114)	(8,233)
Beginning balance at Mar. 31, 2015						(1,047)
Net income	11,556
Other comprehensive income (loss)	(3,067)
Ending balance, preferred stock (shares) at Jun. 30, 2015		2,300,000
Ending balance, common stock (shares) at Jun. 30, 2015			26,871,745
Ending balance at Jun. 30, 2015	$ 523,501	$ 55,569	$ 27,402	359,455	93,422	(4,114)	(8,233)
Beginning balance, preferred stock (shares) at Dec. 31, 2015	2,300,000	2,300,000
Beginning balance, common stock (shares) at Dec. 31, 2015	26,901,801		26,901,801
Beginning balance at Dec. 31, 2015	$ 553,902	$ 55,569	$ 27,432	362,607	124,511	(7,984)	(8,233)
Net income	37,129				37,129
Other comprehensive income (loss)	7,557					7,557
Issuance of stock, net of offering costs (shares)		3,300,000	7,291
Issuance of stock, net of offering costs	159	$ 79,701	$ 7	152
Preferred stock dividends	(3,348)				(3,348)
Share-based compensation expense	2,941			2,941
Exercise of warrants (shares)			239,478
Exercise of warrants	1,071		$ 240	831
Issuance of common stock under share-based compensation arrangements (shares)			138,263
Issuance of common stock under share-based compensation arrangements	$ 1,450		$ 138	1,312
Ending balance, preferred stock (shares) at Jun. 30, 2016	5,600,000	5,600,000
Ending balance, common stock (shares) at Jun. 30, 2016	27,286,833		27,286,833
Ending balance at Jun. 30, 2016	$ 680,562	$ 135,270	$ 27,817	367,843	158,292	(427)	(8,233)
Beginning balance at Mar. 31, 2016						(5,333)
Net income	19,430
Other comprehensive income (loss)	$ 4,906
Ending balance, preferred stock (shares) at Jun. 30, 2016	5,600,000	5,600,000
Ending balance, common stock (shares) at Jun. 30, 2016	27,286,833		27,286,833
Ending balance at Jun. 30, 2016	$ 680,562	$ 135,270	$ 27,817	$ 367,843	$ 158,292	$ (427)	$ (8,233)