Trust Preferred Capital Notes, Debt Items (Details) (USD $) In Thousands, unless otherwise specified								6 Months Ended	9 Months Ended		6 Months Ended	9 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2014 MidCarolina I [Member]	Jul. 01, 2011 MidCarolina I [Member]	Sep. 30, 2014 MidCarolina II [Member]	Jul. 01, 2011 MidCarolina II [Member]	Jul. 01, 2011 MidCarolina Trust [Member]	Sep. 30, 2014 Junior Subordinated Debt Securities [Member]	Dec. 31, 2013 Junior Subordinated Debt Securities [Member]	Jun. 30, 2014 Junior Subordinated Debt Securities [Member] AMNB Trust I [Member]	Sep. 30, 2014 Junior Subordinated Debt Securities [Member] AMNB Trust I [Member]	Dec. 31, 2013 Junior Subordinated Debt Securities [Member] AMNB Trust I [Member]	Jun. 30, 2014 Junior Subordinated Debt Securities [Member] MidCarolina I [Member]	Sep. 30, 2014 Junior Subordinated Debt Securities [Member] MidCarolina I [Member]	Dec. 31, 2013 Junior Subordinated Debt Securities [Member] MidCarolina I [Member]	Jun. 30, 2014 Junior Subordinated Debt Securities [Member] MidCarolina II [Member]	Sep. 30, 2014 Junior Subordinated Debt Securities [Member] MidCarolina II [Member]	Dec. 31, 2013 Junior Subordinated Debt Securities [Member] MidCarolina II [Member]
Debt Instrument [Line Items]
Date Issued									Apr. 07, 2006			Oct. 29, 2002			Dec. 03, 2003
Interest Rate									Libor plus 1.35%			Libor plus 3.45%			Libor plus 2.95%
Variable Rate Basis									Libor plus			Libor plus			Libor plus
Basis Spread on Variable Rate (in hundredths)								1.35%			3.45%			2.95%
Maturity Date									Jun. 30, 2036			Nov. 07, 2032			Oct. 07, 2033
Principal Amount					$ 8,764	$ 27,495	$ 27,419		$ 20,619	$ 20,619		$ 4,140	$ 4,098		$ 2,736	$ 2,702
Valuation allowance associated with junior subordinated debenture	$ 1,015	$ 1,197	$ 872	$ 1,021