Subordinated Debentures (Trust Preferred Securities) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Redemption period, minimum	5 years
Number of deferred consecutive quarterly periods without default or penalty, maximum	20
Accrued but unpaid interest expense	$ 419
Trust Preferred Securities [Member] | Colony Bankcorp Statutory Trust III [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date	Jun. 17, 2004
Amount	4,500
Total rate (in hundredths)	3.06875%
Maturity	Jun. 14, 2034
5 Years Call Option	Jun. 17, 2009
Trust Preferred Securities [Member] | Colony Bankcorp Statutory Trust III [Member] | LIBOR [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
3 month Libor Rate (in hundredths)	0.38875%
Added Points (in hundredths)	2.68%
Trust Preferred Securities [Member] | Colony Bankcorp Capital Trust I [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date	Apr. 13, 2006
Amount	5,000
Total rate (in hundredths)	1.86025%
Maturity	Apr. 13, 2036
5 Years Call Option	Apr. 13, 2011
Trust Preferred Securities [Member] | Colony Bankcorp Capital Trust I [Member] | LIBOR [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
3 month Libor Rate (in hundredths)	0.36025%
Added Points (in hundredths)	1.50%
Trust Preferred Securities [Member] | Colony Bankcorp Capital Trust II [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date	Mar. 12, 2007
Amount	9,000
Total rate (in hundredths)	2.01025%
Maturity	Mar. 12, 2037
5 Years Call Option	Mar. 12, 2012
Trust Preferred Securities [Member] | Colony Bankcorp Capital Trust II [Member] | LIBOR [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
3 month Libor Rate (in hundredths)	0.36025%
Added Points (in hundredths)	1.65%
Trust Preferred Securities [Member] | Colony Bankcorp Capital Trust III [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date	Sep. 14, 2007
Amount	$ 5,000
Total rate (in hundredths)	1.8471%
Maturity	Sep. 14, 2037
5 Years Call Option	Sep. 14, 2012
Trust Preferred Securities [Member] | Colony Bankcorp Capital Trust III [Member] | LIBOR [Member]
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
3 month Libor Rate (in hundredths)	0.4471%
Added Points (in hundredths)	1.40%