Consolidated Statements of Shareholders’ Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Treasury Stock [Member]
Balance at beginning of period at Dec. 31, 2015		$ 33,625	$ 337,349	$ 152,820	$ 3,353	$ (12,388)
Balance at beginning of period, shares at Dec. 31, 2015		33,625,162				1,413,777
Issuance of common stock		$ 2,549	69,906
Issuance of common stock ,shares		2,549,469
Issuance of restricted shares		$ 111	(111)
Issuance of restricted shares, shares		110,653
Forfeitures of restricted shares		$ (3)	3
Forfeitures of restricted shares, shares		(3,085)
Exercise of stock options		$ 21	393
Exercise of stock options, shares		20,964
Share-based compensation			1,009
Net income	$ 32,366			32,366
Dividends on common shares				(3,485)
Other comprehensive income (loss) during the period	9,607				9,607
Purchase of treasury shares						$ (1,210)
Purchase of treasury shares,shares						42,075
Total Shareholders’ Equity at Jun. 30, 2016	625,915	$ 36,303	408,549	181,701	12,960	$ (13,598)
Balance at end of period, shares at Jun. 30, 2016		36,303,163				1,455,852
Balance at beginning of period at Dec. 31, 2016	646,437	$ 36,378	410,276	214,454	(1,058)	$ (13,613)
Balance at beginning of period, shares at Dec. 31, 2016		36,377,807				1,456,333
Issuance of common stock		$ 2,141	92,359
Issuance of common stock ,shares		2,141,072
Issuance of restricted shares		$ 80	(80)
Issuance of restricted shares, shares		80,169
Forfeitures of restricted shares		$ 0	0
Forfeitures of restricted shares, shares		(472)
Exercise of stock options		$ 99	1,751
Exercise of stock options, shares		99,189
Share-based compensation			1,497
Net income	44,240			44,240
Dividends on common shares				(7,435)
Other comprehensive income (loss) during the period	2,479				2,479
Purchase of treasury shares						$ (886)
Purchase of treasury shares,shares						18,528
Total Shareholders’ Equity at Jun. 30, 2017	$ 782,682	$ 38,698	$ 505,803	$ 251,259	$ 1,421	$ (14,499)
Balance at end of period, shares at Jun. 30, 2017		38,697,765				1,474,861