Assets Acquired In FDIC-Assisted Acquisitions (Components Of Covered Assets) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Covered loans	$ 699,229	$ 739,190	$ 841,115
Less: Credit risk adjustments	151,999	166,107	243,597
Less: Liquidity and rate adjustments	996	1,594	2,090
Total covered loans	546,234	571,489	595,428
OREO	106,979	101,685	118,720
Less: Fair value adjustments	18,084	23,068	36,813
Total covered OREO	88,895	78,617	81,907
Total covered assets	635,129	650,106	677,335
FDIC indemnification asset	198,440	242,394	239,719
American United Bank (AUB)
Covered loans	28,955	34,242	39,217
Less: Credit risk adjustments	2,532	3,236	3,594
Less: Liquidity and rate adjustments			64
Total covered loans	26,423	31,006	35,559
OREO	10,342	11,100	13,415
Less: Fair value adjustments			37
Total covered OREO	10,342	11,100	13,378
Total covered assets	36,765	42,106	48,937
FDIC indemnification asset	3,256	7,271	3,215
United Security Bank (USB)
Covered loans	33,145	51,409	58,121
Less: Credit risk adjustments	5,036	5,259	5,913
Less: Liquidity and rate adjustments		50	199
Total covered loans	28,109	46,100	52,009
OREO	7,641	7,445	7,489
Less: Fair value adjustments	99	50	51
Total covered OREO	7,542	7,395	7,438
Total covered assets	35,651	53,495	59,447
FDIC indemnification asset	8,408	10,648	7,431
Satilla Community Bank (SCB)
Covered loans	44,340	56,780	58,748
Less: Credit risk adjustments	3,892	5,779	6,029
Less: Liquidity and rate adjustments		155	258
Total covered loans	40,448	50,846	52,461
OREO	10,464	10,635	10,957
Less: Fair value adjustments	646	500	500
Total covered OREO	9,818	10,135	10,457
Total covered assets	50,266	60,981	62,918
FDIC indemnification asset	6,130	6,527	5,365
First Bank of Jacksonville (FBJ)
Covered loans	33,312	40,106	42,499
Less: Credit risk adjustments	6,299	7,473	8,239
Less: Liquidity and rate adjustments	43	92	108
Total covered loans	26,970	32,541	34,152
OREO	3,407	2,370	3,037
Less: Fair value adjustments	572	641	1,559
Total covered OREO	2,835	1,729	1,478
Total covered assets	29,805	34,270	35,630
FDIC indemnification asset	6,731	8,551	8,863
Darby Bank & Trust (DBT)
Covered loans	186,815	260,883	313,029
Less: Credit risk adjustments	47,598	68,757	112,480
Less: Liquidity and rate adjustments	331	703	827
Total covered loans	138,886	191,423	199,722
OREO	33,404	28,947	35,672
Less: Fair value adjustments	2,798	2,763	8,774
Total covered OREO	30,606	26,184	26,898
Total covered assets	169,492	217,607	226,620
FDIC indemnification asset	63,789	105,528	104,739
Tifton Banking Company (TBC)
Covered loans	51,084	79,586	90,044
Less: Credit risk adjustments	5,790	14,358	18,995
Less: Liquidity and rate adjustments	212	331	371
Total covered loans	45,082	64,897	70,678
OREO	10,110	8,441	6,955
Less: Fair value adjustments	1,533	1,274	1,274
Total covered OREO	8,577	7,167	5,681
Total covered assets	53,659	72,064	76,359
FDIC indemnification asset	15,559	18,628	19,046
High Trust Bank [HTB]
Covered loans	95,904	110,899	129,269
Less: Credit risk adjustments	18,727	28,024	47,738
Less: Liquidity and rate adjustments	56	73	73
Total covered loans	77,121	82,802	81,458
OREO	15,219	20,132	21,953
Less: Fair value adjustments	5,766	10,171	12,618
Total covered OREO	9,453	9,961	9,335
Total covered assets	86,574	92,763	90,793
FDIC indemnification asset	23,698	48,289	47,604
One Georgia Bank (OGB)
Covered loans	86,091	105,285	110,188
Less: Credit risk adjustments	18,719	33,221	40,609
Less: Liquidity and rate adjustments	146	190	190
Total covered loans	67,226	71,874	69,389
OREO	7,874	12,615	19,242
Less: Fair value adjustments	3,663	7,669	12,000
Total covered OREO	4,211	4,946	7,242
Total covered assets	71,437	76,820	76,631
FDIC indemnification asset	21,419	36,952	43,456
Central Bank of Georgia (CBG)
Covered loans	139,583
Less: Credit risk adjustments	43,406
Less: Liquidity and rate adjustments	208
Total covered loans	95,969
OREO	8,518
Less: Fair value adjustments	3,007
Total covered OREO	5,511
Total covered assets	101,480
FDIC indemnification asset	$ 49,450