Financial Instruments with Off-Balance Sheet Credit Risk, Whose Contract Amounts Represent Potential Credit Risk (Detail) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Commitments to Extend Credit | Credit card
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial Instruments with Off-Balance Sheet Credit Risk	$ 3,858,639	$ 3,583,430	$ 3,781,827
Commitments to Extend Credit | Commercial Line of Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial Instruments with Off-Balance Sheet Credit Risk	2,399,225	1,920,056	2,346,902
Commitments to Extend Credit | Other Loan Commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial Instruments with Off-Balance Sheet Credit Risk	368,459	375,565	394,058
Commercial Letters of Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial Instruments with Off-Balance Sheet Credit Risk	18,729	12,532	16,451
Standby Letters of Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial Instruments with Off-Balance Sheet Credit Risk	136,754	140,064	141,893
Mortgage Loan Commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial Instruments with Off-Balance Sheet Credit Risk	$ 35,829	$ 47,493	$ 45,889