Loans (Details) (USD $)	3 Months Ended		9 Months Ended		33 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 item	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Outstanding loan balances
Total gross loans	$ 777,154,000		$ 777,154,000		$ 777,154,000		$ 689,608,000
Net deferred loan fees	(1,454,000)		(1,454,000)		(1,454,000)		(937,000)
Allowance for loan losses	(17,468,000)	(17,987,000)	(17,468,000)	(17,987,000)	(17,468,000)	(17,934,000)	(18,118,000)	(18,149,000)	(19,314,000)
Net loans held for investment	758,232,000		758,232,000		758,232,000		670,553,000
Loans held for sale	5,463,000		5,463,000		5,463,000		22,549,000
Reserve maintained for the exercise of repurchase option by buyer	500,000		500,000		500,000
Losses incurred on settlement					1,400,000
Number of loans settled					9
Concentration of Credit Risk
Loan portfolio collateralized by various forms of real estate	641,300,000		641,300,000		641,300,000		537,400,000
Loans Serviced for Others
Unpaid principal balance of loans serviced for others, exclusive of SBA loans	20,100,000		20,100,000		20,100,000		7,100,000
Unpaid principal balance of SBA loans serviced for others	6,800,000		6,800,000		6,800,000		3,100,000
Recognized gains from the sale of SBA loans	400,000	0	400,000	0
Minimum
Outstanding loan balances
Period for sale of loans categorized as held for sale			30 days
Maximum
Outstanding loan balances
Period for sale of loans categorized as held for sale			60 days
Real Estate Secured
Outstanding loan balances
Total gross loans	603,081,000		603,081,000		603,081,000		493,008,000
Allowance for loan losses	(6,307,000)	(7,987,000)	(6,307,000)	(7,987,000)	(6,307,000)	(6,509,000)	(6,879,000)	(6,897,000)	(9,645,000)
Real Estate Secured | Multi-family residential
Outstanding loan balances
Total gross loans	25,782,000		25,782,000		25,782,000		21,467,000
Real Estate Secured | Residential 1 to 4 family
Outstanding loan balances
Total gross loans	57,016,000		57,016,000		57,016,000		41,444,000
Real Estate Secured | Home equity lines of credit
Outstanding loan balances
Total gross loans	32,388,000		32,388,000		32,388,000		31,863,000
Real Estate Secured | Commercial
Outstanding loan balances
Total gross loans	442,322,000		442,322,000		442,322,000		372,592,000
Real Estate Secured | Farmland
Outstanding loan balances
Total gross loans	45,573,000		45,573,000		45,573,000		25,642,000
Commercial
Outstanding loan balances
Total gross loans	132,107,000		132,107,000		132,107,000		147,064,000
Allowance for loan losses	(6,150,000)	(5,071,000)	(6,150,000)	(5,071,000)	(6,150,000)	(6,618,000)	(6,154,000)	(6,261,000)	(6,549,000)
Commercial | Commercial and industrial
Outstanding loan balances
Total gross loans	103,540,000		103,540,000		103,540,000		125,340,000
Commercial | Agriculture
Outstanding loan balances
Total gross loans	28,523,000		28,523,000		28,523,000		21,663,000
Commercial | Other
Outstanding loan balances
Total gross loans	44,000		44,000		44,000		61,000
Construction
Outstanding loan balances
Total gross loans	13,174,000		13,174,000		13,174,000		19,716,000
Allowance for loan losses	(243,000)	(558,000)	(243,000)	(558,000)	(243,000)	(198,000)	(313,000)	(381,000)	(488,000)
Construction | Single family residential
Outstanding loan balances
Total gross loans	4,619,000		4,619,000		4,619,000		8,074,000
Construction | Single family residential - Spec.
Outstanding loan balances
Total gross loans	1,114,000		1,114,000		1,114,000		535,000
Construction | Multi-family
Outstanding loan balances
Total gross loans	747,000		747,000		747,000		778,000
Construction | Commercial
Outstanding loan balances
Total gross loans	6,694,000		6,694,000		6,694,000		10,329,000
Land
Outstanding loan balances
Total gross loans	25,042,000		25,042,000		25,042,000		24,664,000
Allowance for loan losses	(4,646,000)	(4,263,000)	(4,646,000)	(4,263,000)	(4,646,000)	(4,465,000)	(4,670,000)	(4,483,000)	(2,416,000)
Installment loans to individuals
Outstanding loan balances
Total gross loans	3,495,000		3,495,000		3,495,000		4,895,000
Allowance for loan losses	(87,000)	(72,000)	(87,000)	(72,000)	(87,000)	(108,000)	(64,000)	(91,000)	(175,000)
All other loans (including overdrafts)
Outstanding loan balances
Total gross loans	255,000		255,000		255,000		261,000
Allowance for loan losses	$ (35,000)	$ (36,000)	$ (35,000)	$ (36,000)	$ (35,000)	$ (36,000)	$ (38,000)	$ (36,000)	$ (41,000)