Commitments, Guarantees and Other Contingencies - Schedule of Contractual Obligations of Time Deposit Accounts (Detail) (Time deposit accounts [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Time deposit accounts [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Less than one year	$ 266,786
Over one through three years	74,082
Over three through five years	4,742
Over five years	59
Total	$ 345,669