Loan Portfolio, Past Due (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	$ 1,625,000	$ 2,264,000
60 to 89 Days Past Due	1,176,000	1,091,000
90 Days Or Greater	10,868,000	10,241,000
Total Past Due	13,669,000	13,596,000
Current	700,917,000	695,881,000
Total ending loan balances	714,586,000	709,477,000
Nonaccrual	20,019,000	21,664,000
Past due 90 days or more and still accruing	812,000	1,044,000
Interest on non-accrual loans foregone	297,000.0	1,350,000
Real Estate Loans Construction [Member]
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	0	0
60 to 89 Days Past Due	591,000	108,000
90 Days Or Greater	1,964,000	2,043,000
Total Past Due	2,555,000	2,151,000
Current	43,534,000	48,067,000
Total ending loan balances	46,089,000	50,218,000
Nonaccrual	2,790,000	2,861,000
Past due 90 days or more and still accruing	268,000	780,000
Real Estate Loans Secured by Farmland [Member]
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	415,000	415,000
60 to 89 Days Past Due	0	0
90 Days Or Greater	0	0
Total Past Due	415,000	415,000
Current	11,390,000	11,461,000
Total ending loan balances	11,805,000	11,876,000
Real Estate Loans Secured by 1 - 4 Family Residential [Member]
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	796,000	1,625,000
60 to 89 Days Past Due	244,000	568,000
90 Days Or Greater	2,308,000	1,910,000
Total Past Due	3,348,000	4,103,000
Current	265,422,000	256,517,000
Total ending loan balances	268,770,000	260,620,000
Nonaccrual	8,396,000	8,761,000
Past due 90 days or more and still accruing	532,000	228,000
Other Real Estate Loans [Member]
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	391,000	197,000
60 to 89 Days Past Due	194,000	361,000
90 Days Or Greater	4,648,000	6,112,000
Total Past Due	5,233,000	6,670,000
Current	254,170,000	248,260,000
Total ending loan balances	259,403,000	254,930,000
Nonaccrual	6,663,000	7,866,000
Past due 90 days or more and still accruing	0	0
Commercial Loans [Member]
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	0	0
60 to 89 Days Past Due	145,000	44,000
90 Days Or Greater	1,906,000	144,000
Total Past Due	2,051,000	188,000
Current	113,970,000	118,385,000
Total ending loan balances	116,021,000	118,573,000
Nonaccrual	2,140,000	2,146,000
Past due 90 days or more and still accruing	0	34,000
Consumer Loans [Member]
Past due loans by class of loans [Abstract]
30 to 59 Days Past Due	23,000	27,000
60 to 89 Days Past Due	2,000	10,000
90 Days Or Greater	42,000	32,000
Total Past Due	67,000	69,000
Current	12,431,000	13,191,000
Total ending loan balances	12,498,000	13,260,000
Nonaccrual	30,000	30,000
Past due 90 days or more and still accruing	$ 12,000	$ 2,000