Assets Acquired In FDIC-Assisted Acquisitions - Covered Loans with Deterioration of Credit Quality on Respective Acquisition Dates (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Estimated Fair value of loans acquired	$ 887,598
Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	470,602
Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	416,996
Construction And Development [Member]
Estimated Fair value of loans acquired	152,118
Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	96,960
Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	55,158
Real Estate Secured [Member]
Estimated Fair value of loans acquired	612,317
Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	334,391
Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	277,926
Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	101,789
Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	37,015
Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	64,774
Consumer [Member]
Estimated Fair value of loans acquired	21,374
Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	2,236
Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	19,138
American United Bank (AUB) [Member]
Estimated Fair value of loans acquired	56,482
American United Bank (AUB) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	37,077
American United Bank (AUB) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	19,405
American United Bank (AUB) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	17,504
American United Bank (AUB) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	16,513
American United Bank (AUB) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	991
American United Bank (AUB) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	12,043
American United Bank (AUB) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	8,460
American United Bank (AUB) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	3,583
American United Bank (AUB) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	26,495
American United Bank (AUB) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	12,102
American United Bank (AUB) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	14,393
American United Bank (AUB) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	440
American United Bank (AUB) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	2
American United Bank (AUB) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	438
United Security Bank (USB) [Member]
Estimated Fair value of loans acquired	83,646
United Security Bank (USB) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	21,475
United Security Bank (USB) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	62,171
United Security Bank (USB) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	30,276
United Security Bank (USB) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	16,086
United Security Bank (USB) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	14,190
United Security Bank (USB) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	41,087
United Security Bank (USB) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	3,987
United Security Bank (USB) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	37,100
United Security Bank (USB) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	6,904
United Security Bank (USB) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	769
United Security Bank (USB) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	6,135
United Security Bank (USB) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	5,379
United Security Bank (USB) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	633
United Security Bank (USB) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	4,746
Satilla Community Bank (SCB) [Member]
Estimated Fair value of loans acquired	68,751
Satilla Community Bank (SCB) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	25,471
Satilla Community Bank (SCB) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	43,280
Satilla Community Bank (SCB) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	16,800
Satilla Community Bank (SCB) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	8,976
Satilla Community Bank (SCB) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	7,824
Satilla Community Bank (SCB) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	49,582
Satilla Community Bank (SCB) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	16,422
Satilla Community Bank (SCB) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	33,160
Satilla Community Bank (SCB) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	1,641
Satilla Community Bank (SCB) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	73
Satilla Community Bank (SCB) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	1,568
Satilla Community Bank (SCB) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	728
Satilla Community Bank (SCB) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	728
First Bank of Jacksonville (FBJ) [Member]
Estimated Fair value of loans acquired	40,454
First Bank of Jacksonville (FBJ) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	19,238
First Bank of Jacksonville (FBJ) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	21,216
First Bank of Jacksonville (FBJ) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	7,984
First Bank of Jacksonville (FBJ) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	4,821
First Bank of Jacksonville (FBJ) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	3,163
First Bank of Jacksonville (FBJ) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	30,319
First Bank of Jacksonville (FBJ) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	13,279
First Bank of Jacksonville (FBJ) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	17,040
First Bank of Jacksonville (FBJ) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	1,412
First Bank of Jacksonville (FBJ) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	886
First Bank of Jacksonville (FBJ) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	526
First Bank of Jacksonville (FBJ) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	739
First Bank of Jacksonville (FBJ) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	252
First Bank of Jacksonville (FBJ) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	487
Tifton Banking Company (TBC) [Member]
Estimated Fair value of loans acquired	92,568
Tifton Banking Company (TBC) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	29,973
Tifton Banking Company (TBC) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	62,595
Tifton Banking Company (TBC) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	6,948
Tifton Banking Company (TBC) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	2,435
Tifton Banking Company (TBC) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	4,513
Tifton Banking Company (TBC) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	54,361
Tifton Banking Company (TBC) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	20,305
Tifton Banking Company (TBC) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	34,056
Tifton Banking Company (TBC) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	29,394
Tifton Banking Company (TBC) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	7,134
Tifton Banking Company (TBC) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	22,260
Tifton Banking Company (TBC) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	1,865
Tifton Banking Company (TBC) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	99
Tifton Banking Company (TBC) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	1,766
Darby Bank & Trust (DBT) [Member]
Estimated Fair value of loans acquired	261,340
Darby Bank & Trust (DBT) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	139,818
Darby Bank & Trust (DBT) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	121,522
Darby Bank & Trust (DBT) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	37,371
Darby Bank & Trust (DBT) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	21,800
Darby Bank & Trust (DBT) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	15,571
Darby Bank & Trust (DBT) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	203,070
Darby Bank & Trust (DBT) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	111,973
Darby Bank & Trust (DBT) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	91,097
Darby Bank & Trust (DBT) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	17,270
Darby Bank & Trust (DBT) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	5,379
Darby Bank & Trust (DBT) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	11,891
Darby Bank & Trust (DBT) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	3,629
Darby Bank & Trust (DBT) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	666
Darby Bank & Trust (DBT) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	2,963
High Trust Bank [HTB] [Member]
Estimated Fair value of loans acquired	84,732
High Trust Bank [HTB] [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	74,216
High Trust Bank [HTB] [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	10,516
High Trust Bank [HTB] [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	6,561
High Trust Bank [HTB] [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	6,508
High Trust Bank [HTB] [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	53
High Trust Bank [HTB] [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	76,920
High Trust Bank [HTB] [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	67,497
High Trust Bank [HTB] [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	9,423
High Trust Bank [HTB] [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	395
High Trust Bank [HTB] [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	153
High Trust Bank [HTB] [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	242
High Trust Bank [HTB] [Member] | Consumer [Member]
Estimated Fair value of loans acquired	856
High Trust Bank [HTB] [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	58
High Trust Bank [HTB] [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	798
One Georgia Bank (OGB) [Member]
Estimated Fair value of loans acquired	74,843
One Georgia Bank (OGB) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	49,920
One Georgia Bank (OGB) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	24,923
One Georgia Bank (OGB) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	8,129
One Georgia Bank (OGB) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	4,783
One Georgia Bank (OGB) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	3,346
One Georgia Bank (OGB) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	55,337
One Georgia Bank (OGB) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	35,621
One Georgia Bank (OGB) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	19,716
One Georgia Bank (OGB) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	10,734
One Georgia Bank (OGB) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	9,263
One Georgia Bank (OGB) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	1,471
One Georgia Bank (OGB) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	643
One Georgia Bank (OGB) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	253
One Georgia Bank (OGB) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	390
Central Bank of Georgia (CBG) [Member]
Estimated Fair value of loans acquired	124,782
Central Bank of Georgia (CBG) [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	73,414
Central Bank of Georgia (CBG) [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	51,368
Central Bank of Georgia (CBG) [Member] | Construction And Development [Member]
Estimated Fair value of loans acquired	20,545
Central Bank of Georgia (CBG) [Member] | Construction And Development [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	15,038
Central Bank of Georgia (CBG) [Member] | Construction And Development [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	5,507
Central Bank of Georgia (CBG) [Member] | Real Estate Secured [Member]
Estimated Fair value of loans acquired	89,598
Central Bank of Georgia (CBG) [Member] | Real Estate Secured [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	56,847
Central Bank of Georgia (CBG) [Member] | Real Estate Secured [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	32,751
Central Bank of Georgia (CBG) [Member] | Commercial Industrial Agricultural [Member]
Estimated Fair value of loans acquired	7,544
Central Bank of Georgia (CBG) [Member] | Commercial Industrial Agricultural [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	1,256
Central Bank of Georgia (CBG) [Member] | Commercial Industrial Agricultural [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	6,288
Central Bank of Georgia (CBG) [Member] | Consumer [Member]
Estimated Fair value of loans acquired	7,095
Central Bank of Georgia (CBG) [Member] | Consumer [Member] | Loans With Deterioration Of Credit Quality [Member]
Estimated Fair value of loans acquired	273
Central Bank of Georgia (CBG) [Member] | Consumer [Member] | Loans without Deterioration of Credit Quality [Member]
Estimated Fair value of loans acquired	$ 6,822