Assets Acquired In FDIC-Assisted Acquisitions - Summary of Total Assets Purchased and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended	34 Months Ended
	Dec. 31, 2013	Jul. 31, 2012
American United Bank (AUB) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Oct. 23, 2009	Oct. 23, 2009
Assets, fair value	$ 120,994
Deposits, fair value	100,470
Other borrowings	7,802
Discount bid	19,645
Deposit premium	262
Cash received/(paid)	17,100
Gain/(Goodwill)	12,445
American United Bank (AUB) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	38,000
Percentage retained by FDIC	80.00%
American United Bank (AUB) [Member] | Tranche Two [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	95.00%
American United Bank (AUB) [Member] | Minimum [Member] | Tranche Two [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	38,000
United Security Bank (USB) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Nov. 06, 2009	Nov. 06, 2009
Assets, fair value	169,172
Deposits, fair value	141,094
Other borrowings	1,504
Discount bid	32,615
Deposit premium	228
Cash received/(paid)	24,200
Gain/(Goodwill)	26,121
United Security Bank (USB) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	46,000
Percentage retained by FDIC	80.00%
United Security Bank (USB) [Member] | Tranche Two [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	95.00%
United Security Bank (USB) [Member] | Minimum [Member] | Tranche Two [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	46,000
Satilla Community Bank (SCB) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	May 14, 2010	May 14, 2010
Assets, fair value	84,342
Deposits, fair value	75,530
Discount bid	14,395
Deposit premium	92
Cash received/(paid)	(35,657)
Gain/(Goodwill)	8,208
Satilla Community Bank (SCB) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
First Bank of Jacksonville (FBJ) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Oct. 22, 2010	Oct. 22, 2010
Assets, fair value	77,709
Deposits, fair value	71,869
Other borrowings	2,613
Discount bid	4,810
Cash received/(paid)	8,117
Gain/(Goodwill)	2,385
First Bank of Jacksonville (FBJ) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
Tifton Banking Company (TBC) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Nov. 12, 2010	Nov. 12, 2010
Assets, fair value	132,036
Deposits, fair value	132,939
Discount bid	3,973
Cash received/(paid)	(10,251)
Gain/(Goodwill)	(956)
Tifton Banking Company (TBC) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
Darby Bank & Trust (DBT) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Nov. 12, 2010	Nov. 12, 2010
Assets, fair value	448,311
Deposits, fair value	386,958
Other borrowings	54,418
Discount bid	45,002
Cash received/(paid)	(149,893)
Gain/(Goodwill)	4,211
Darby Bank & Trust (DBT) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	131,772
Percentage retained by FDIC	80.00%
Darby Bank & Trust (DBT) [Member] | Tranche Two [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	30.00%
Darby Bank & Trust (DBT) [Member] | Tranche 3 [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
Darby Bank & Trust (DBT) [Member] | Minimum [Member] | Tranche Two [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	193,068
Darby Bank & Trust (DBT) [Member] | Minimum [Member] | Tranche 3 [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
FDIC loss sharing - Tranche Cumulative Loss threshold	193,068
High Trust Bank (HTB) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Jul. 15, 2011	Jul. 15, 2011
Assets, fair value	197,463
Deposits, fair value	175,887
Discount bid	33,500
Cash received/(paid)	30,228
Gain/(Goodwill)	18,922
High Trust Bank (HTB) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
One Georgia Bank (OGB) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Jul. 15, 2011	Jul. 15, 2011
Assets, fair value	166,052
Deposits, fair value	136,101
Other borrowings	21,107
Discount bid	22,500
Cash received/(paid)	(5,658)
Gain/(Goodwill)	7,945
One Georgia Bank (OGB) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
Central Bank of Georgia (CBG) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Feb. 24, 2012	Feb. 24, 2012
Assets, fair value	293,189
Deposits, fair value	261,036
Other borrowings	10,334
Discount bid	33,900
Cash received/(paid)	31,900
Gain/(Goodwill)	20,037
Central Bank of Georgia (CBG) [Member] | Tranche One [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Percentage retained by FDIC	80.00%
Montgomery Bank & Trust (MBT) [Member]
Schedule of Business Acquisitions by Acquisition Purchase Price Allocation [Line Items]
Acquisition date	Jul. 06, 2012	Jul. 06, 2012
Assets, fair value	156,867
Deposits, fair value	156,699
Cash received/(paid)	$ 138,740