Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Capital Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance at beginning of period at Dec. 31, 2014	$ 496,317	$ 81,698	$ 18,511	$ 95,816	$ 298,764	$ 1,528	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	19,436				15,709	3,727
Cash dividends declared:
Series C Preferred, $2.50 per share	(204)				(204)
Common, $0.10 per share	(2,057)				(2,057)
Purchase of shares of common stock	(1,780)						(1,780)
Issuance of shares of common stock	54,496		2,075	50,687			1,734
Stock based compensation	1,139			1,139
Balance at end of period at Mar. 31, 2015	567,347	81,698	20,586	147,642	312,212	5,255	(46)
Balance at beginning of period at Dec. 31, 2015	663,173	81,698	22,436	216,436	348,630	(6,027)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	27,960				20,009	7,951
Cash dividends declared:
Series C Preferred, $2.50 per share	(168)				(168)
Common, $0.10 per share	(2,457)				(2,457)
Redemption of Series C preferred stock	(81,698)	(81,698)
Issuance of Series D preferred stock	3,777	3,777
Purchase of shares of common stock	(1,227)						(1,227)
Issuance of shares of common stock	59,096		2,084	55,787			1,225
Stock based compensation	1,087			1,087
Balance at end of period at Mar. 31, 2016	$ 669,543	$ 3,777	$ 24,520	$ 273,310	$ 366,014	$ 1,924	$ (2)