Consolidated Statements of Changes in Shareholders' Equity - 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, 2013		0
Beginning balance, common stock, shares at Dec. 31, 2013			24,224,151
Beginning balance at Dec. 31, 2013	$ 386,623	$ 0	$ 24,756	$ 307,231	$ 71,008	$ (8,118)	$ (8,254)
Net income	30,036				30,036
Other comprehensive income (loss)	5,098					5,098
Stock dividend, shares			2,429,375
Stock dividend	(6)		$ 2,429	43,364	(45,799)
Share-based compensation expense	3,124			3,124
Issuance of common stock under share-based compensation arrangements, shares			81,509
Issuance of common stock under share-based compensation arrangements	924		$ 82	842
Ending balance, preferred stock, shares at Sep. 30, 2014		0
Ending balance, common stock, shares at Sep. 30, 2014			26,735,035
Ending balance at Sep. 30, 2014	$ 425,799	$ 0	$ 27,267	354,561	55,245	(3,020)	(8,254)
Beginning balance, preferred stock, shares at Dec. 31, 2014		0
Beginning balance, common stock, shares at Dec. 31, 2014	26,745,529		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 preferred stock, net of offering costs, shares		2,300,000
Issuance of preferred stock, net of offering costs	55,569	$ 55,569
Preferred stock dividend	(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		26,882,383
Ending balance at Sep. 30, 2015	$ 537,978	$ 55,569	$ 27,413	$ 360,903	$ 107,731	$ (5,405)	$ (8,233)