Assets Acquired in FDIC-Assisted Acquisition - Additional Information (Detail) (USD $)	34 Months Ended				12 Months Ended
	Jul. 31, 2012 Acquisition	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Central Bank of Georgia (CBG) [Member]	Dec. 31, 2011 High Trust Bank and One Georgia Bank [Member]
Business Acquisition [Line Items]
Number of FDIC-assisted acquisitions participation	10
Assets acquisitions					$ 20,000,000	$ 26,900,000
Deferred tax liability recorded with respect to acquisition					7,000,000	9,400,000
After-tax gain on acquisition					13,000,000	17,500,000
Estimated FDIC indemnification asset		$ 65,441,000	$ 159,724,000	$ 242,394,000	$ 52,700,000