Loans and Allowance for Loan Losses - Summary of Maturities of Loan Portfolio (Details) (Commercial Financial And Agricultural And Construction [Member], USD $)	Jun. 30, 2013
Commercial Financial And Agricultural And Construction [Member]
In one year or less	$ 20,595,634
After one year but within five years	32,271,178
After five years	5,839,198
Total	$ 58,706,010

Distribution of loans which are due after one year but within five years..

No definition available.

Name:	SGB_DistributionOfLoansWhichAreDueAfterOneYearButWithinFiveYears
Namespace Prefix:	SGB_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant