Merger with MidCarolina (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jul. 01, 2011
Merger with MidCarolina [Abstract]
Effective date of completion of merger					Jul. 01, 2011
Date of acquisition agreement					Dec. 15, 2010
Number of branches added during expansion of business					8
Number of shares received by the stockholder of acquiree entity in exchange of acquirer entity's common stock (in shares)					0.33
Shares exchange ratio on acquisition					0.33
Number of additional common stock issued in connection with merger (in shares)			1,626,157
Percentage of outstanding common stock in connection with merger (in hundredths)	20.80%		20.80%
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Amortization period of core deposit			9 years
Liabilities assumed:
Goodwill resulting from merger with MidCarolina	$ 39,352,000		$ 39,352,000		$ 38,899,000
Changes in the fair value of net assets acquired and liabilities assumed [Abstract]
Goodwill, beginning of period			38,899,000
Effect of adjustments to:
Goodwill, end of period	39,352,000		39,352,000		38,899,000
Acquired loan portfolio at fair value					367,400,000
Discount on acquired loan portfolio at fair value					39,900,000
Performing portion of acquired loan portfolio estimated at fair value					286,500,000
Direct costs related to acquisition expense	(202,000)	835,000	49,000	1,144,000	1,600,000
Details the acquired loans that are accounted for in accordance with FASB ASC 310-30 [Abstract]
Contractually required principal and interest at acquisition						56,681,000
Contractual cash flows not expected to be collected (nonaccretable difference)						17,472,000
Expected cash flows at acquisition						39,209,000
Interest component of expected cash flows (accretable discount)						1,663,000
Fair value of acquired loans accounted for under FASB ASC 310-30						37,546,000
Unaudited pro forma information related to merger [Abstract]
Net interest income				27,429,000
Provision for loan loss				(3,073,000)
Non-interest income				5,014,000
Non-interest expense				(21,506,000)
Income taxes				(2,359,000)
Net income				5,505,000
MidCarolina [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Amortization period of core deposit			108 months
Consideration Paid:
Common shares issued (1,626,157)	29,905,000		29,905,000
Cash paid to Shareholders	12,000		12,000
Fair Value of Options	132,000		132,000
Preferred shares issued (5,000)	5,000,000		5,000,000
Value of consideration	35,049,000		35,049,000
Assets acquired:
Cash and cash equivalents	34,783,000		34,783,000
Investment securities	51,442,000		51,442,000
Loans held for sale	113,000		113,000
Loans, net of unearned income	328,123,000		328,123,000
Premises and equipment, net	5,708,000		5,708,000
Deferred income taxes	15,310,000		15,310,000
Core deposit intangible	6,556,000		6,556,000
Other real estate owned	3,538,000		3,538,000
Other assets	13,535,000		13,535,000
Total assets	459,108,000		459,108,000
Liabilities assumed:
Deposits	420,248,000		420,248,000
FHLB advances	9,858,000		9,858,000
Other borrowings	6,546,000		6,546,000
Other liabilities	4,291,000		4,291,000
Total Liabilities	440,943,000		440,943,000
Net assets acquired	18,165,000		18,165,000
Goodwill resulting from merger with MidCarolina	16,884,000		16,884,000
Changes in the fair value of net assets acquired and liabilities assumed [Abstract]
Goodwill, beginning of period			16,431,000
Effect of adjustments to:
Other liabilities			453,000
Goodwill, end of period	16,884,000		16,884,000
Series A preferred stock [Member] | MidCarolina [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Number of perpetual Series A preferred stock received in exchange on merger (in shares)					1
Number of Series A preferred stock repurchased, earlier issued (in shares)					5,000
Preferred stock, liquidation preference in connection of merger (in dollars per share)					$ 1,000
Percentage of redemption preferred stock at par (in hundredths)					104.50%
Percentage of value of par paid by entity (in hundredths)					62.00%
Aggregate purchase price to repurchase shares					$ 3,100,000