Consolidated Statements of Stockholders' Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]
Beginning balance at Dec. 31, 2012	$ 235,387	$ 400	$ 14,131	$ 157,305	$ 56,311	$ 7,240
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,369	0	0	0	12,369	0
Other comprehensive (loss) income	(17,885)	0	0	0	0	(17,885)
Dividends declared on preferred stock	(60)	0	0	0	(60)	0
Common stock issued under stock option plans, including tax benefit	252	0	18	234	0	0
Common stock issued under employee stock purchase plan	1	0	0	1	0	0
Proceeds from issuance of common stock in connection with dividend reinvestment and stock purchase plan	70	0	2	68	0	0
Common stock share-based awards	807	0	0	807	0	0
Ending balance at Sep. 30, 2013	230,941	400	14,151	158,415	68,620	(10,645)
Beginning balance at Dec. 31, 2013	230,183	400	14,157	158,650	73,491	(16,515)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,526	0	0	0	15,526	0
Other comprehensive (loss) income	6,432	0	0	0	0	6,432
Dividends declared on preferred stock	(60)	0	0	0	(60)	0
Common stock issued under stock option plans, including tax benefit	694	0	47	647	0	0
Common stock issued under employee stock purchase plan	0	0	0	0	0	0
Proceeds from issuance of common stock in connection with dividend reinvestment and stock purchase plan	43	0	2	41	0	0
Common stock share-based awards	544	0	0	544	0	0
Ending balance at Sep. 30, 2014	$ 253,362	$ 400	$ 14,206	$ 159,882	$ 88,957	$ (10,083)