Commitments, Guarantees, And Contingent Liabilities (Contractual Or Notional Amounts Of Financial Instruments) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Commitments Guarantees And Contingent Liabilities [Line Items]
Home equity lines	$ 157,316	$ 159,072
Residential 1-4 family construction	36,315	34,167
Commercial real estate	635,038	539,667
Commercial and industrial	3,251,537	3,197,347
All other commitments	188,984	176,916
Total commitments to extend credit	4,269,190	4,107,169
Financial standby	278,589	341,502
Performance standby	26,142	26,212
Commercial letters of credit	4,765	2,127
Total letters of credit	$ 309,496	$ 369,841