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 Income/(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	40,797				40,797
Other comprehensive income (loss)	(5,283)					(5,283)
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	(1,487)				(1,487)
Share-based compensation expense	3,541			3,541
Issuance of common stock under share-based compensation arrangements (shares)			136,854
Issuance of common stock under share-based compensation arrangements	1,696		$ 135	1,540			21
Ending balance, preferred stock (shares) at Sep. 30, 2015		2,300,000
Ending balance, common stock (shares) at Sep. 30, 2015			26,882,383
Ending balance at Sep. 30, 2015	537,978	$ 55,569	$ 27,413	360,903	107,731	(5,405)	(8,233)
Beginning balance at Jun. 30, 2015						(4,114)
Net income	15,289
Other comprehensive income (loss)	(1,291)
Ending balance, preferred stock (shares) at Sep. 30, 2015		2,300,000
Ending balance, common stock (shares) at Sep. 30, 2015			26,882,383
Ending balance at Sep. 30, 2015	$ 537,978	$ 55,569	$ 27,413	360,903	107,731	(5,405)	(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	58,318				58,318
Other comprehensive income (loss)	8,758					8,758
Issuance of stock, net of offering costs (shares)		6,700,000	226,677
Issuance of stock, net of offering costs	5,677	$ 161,980	$ 227	5,450
Preferred stock dividends	(5,900)				(5,900)
Share-based compensation expense	4,569			4,569
Exercise of warrants (shares)			259,851
Exercise of warrants	1,121		$ 259	862
Issuance of common stock under share-based compensation arrangements (shares)			155,888
Issuance of common stock under share-based compensation arrangements	$ 1,395		$ 156	1,239
Ending balance, preferred stock (shares) at Sep. 30, 2016	9,000,000	9,000,000
Ending balance, common stock (shares) at Sep. 30, 2016	27,544,217		27,544,217
Ending balance at Sep. 30, 2016	$ 789,820	$ 217,549	$ 28,074	374,727	176,929	774	(8,233)
Beginning balance at Jun. 30, 2016						(427)
Net income	21,189
Other comprehensive income (loss)	$ 1,201
Ending balance, preferred stock (shares) at Sep. 30, 2016	9,000,000	9,000,000
Ending balance, common stock (shares) at Sep. 30, 2016	27,544,217		27,544,217
Ending balance at Sep. 30, 2016	$ 789,820	$ 217,549	$ 28,074	$ 374,727	$ 176,929	$ 774	$ (8,233)