Loans and Allowance for Loan Losses - Summary of Maturities of Loan Portfolio (Details) (Commercial Financial And Agricultural And Construction [Member], USD $)	Jun. 30, 2012
Commercial Financial And Agricultural And Construction [Member]
In one year or less	$ 16,342,107
After one year but within five years	34,418,113
After five years	6,391,321
Total	$ 57,151,541

Distribution Of Loans Which Are Due After One Year But Within Five Years

No definition available.

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