Subsequent Events (Details) (USD $) In Thousands, unless otherwise specified					0 Months Ended	9 Months Ended	0 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010	Oct. 20, 2012 Subsequent Event property	Sep. 30, 2012 Subsequent Event	Oct. 20, 2012 Subsequent Event CBT	Oct. 20, 2012 Subsequent Event Habersham Bank
Savannah Bancorp, Inc. - Definitive Agreement
Number of covered properties auctioned					175
Percentage of loan and foreclosed real estate losses covered by FDIC							95.00%	80.00%
Other real estate owned, covered (in dollars)	$ 47,063	$ 65,849	$ 79,740	$ 69,317	$ 9,200
Decrease in carrying amount (as a percent)						20.00%