Assets Acquired In FDIC-Assisted Acquisitions (Estimated Fair Values Of Loans Acquired) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Estimated fair values of loans acquired	$ 1,975,541
Central Bank of Georgia (CBG)
Estimated fair values of loans acquired	124,782
Central Bank of Georgia (CBG) | Commercial, industrial, agricultural
Estimated fair values of loans acquired	7,544
Central Bank of Georgia (CBG) | Real estate - residential
Estimated fair values of loans acquired	44,602
Central Bank of Georgia (CBG) | Real estate - commercial and farmland
Estimated fair values of loans acquired	44,996
Central Bank of Georgia (CBG) | Construction & development
Estimated fair values of loans acquired	20,545
Central Bank of Georgia (CBG) | Consumer
Estimated fair values of loans acquired	7,095
Loans with Deterioration of Credit Quality | Central Bank of Georgia (CBG)
Estimated fair values of loans acquired	73,414
Loans with Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Commercial, industrial, agricultural
Estimated fair values of loans acquired	1,256
Loans with Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Real estate - residential
Estimated fair values of loans acquired	22,389
Loans with Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Real estate - commercial and farmland
Estimated fair values of loans acquired	34,458
Loans with Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Construction & development
Estimated fair values of loans acquired	15,038
Loans with Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Consumer
Estimated fair values of loans acquired	273
Loans without Deterioration of Credit Quality | Central Bank of Georgia (CBG)
Estimated fair values of loans acquired	51,368
Loans without Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Commercial, industrial, agricultural
Estimated fair values of loans acquired	6,288
Loans without Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Real estate - residential
Estimated fair values of loans acquired	22,213
Loans without Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Real estate - commercial and farmland
Estimated fair values of loans acquired	10,538
Loans without Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Construction & development
Estimated fair values of loans acquired	5,507
Loans without Deterioration of Credit Quality | Central Bank of Georgia (CBG) | Consumer
Estimated fair values of loans acquired	$ 6,822