Commitments, Contingencies and Guarantees - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016 USD ($) attorney_general	Sep. 30, 2014 USD ($)
Loss Contingencies [Line Items]
Contractual obligation	$ 429,000,000
Other liabilities reserve	$ 100,000
Loss contingency, loss emergence period	1 year
FDIC civil monetary penalties		$ 3,300,000
Number of Attorney Generals | attorney_general	2
Maximum
Loss Contingencies [Line Items]
Contingency refund	$ 30,000,000