Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Derivative [Line Items]
Fair Value	$ 80,825		$ 104,955
Collateral			37,245	[1]
Net Exposure	80,825	[2]	67,710	[2]
Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps | Other assets
Derivative [Line Items]
Notional or Contractual Amount	187,393		500,000
Fair value	11,441		52,017
Collateral			37,245	[1]
Net Exposure	11,441	[2]	14,772	[2]
Derivatives not designated as hedging instruments | Currency exchange risks
Derivative [Line Items]
Fair Value	315		179
Net Exposure	315	[2]	179	[2]
Derivatives not designated as hedging instruments | Currency exchange risks | Foreign exchange forwards | Other assets
Derivative [Line Items]
Notional or Contractual Amount	68,518		33,046
Fair value	514		459
Net Exposure	514	[2]	459	[2]
Derivatives not designated as hedging instruments | Currency exchange risks | Foreign exchange forwards | Other liability
Derivative [Line Items]
Notional or Contractual Amount	6,822		26,764
Fair Value	(199)		(280)
Net Exposure	(199)	[2]	(280)	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Equity Warrant Asset | Other assets
Derivative [Line Items]
Notional or Contractual Amount	144,586		126,062
Fair value	66,953		47,565
Net Exposure	66,953	[2]	47,565	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives
Derivative [Line Items]
Fair Value	2,116		5,194
Net Exposure	2,116	[2]	5,194	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Foreign exchange forwards | Other assets
Derivative [Line Items]
Notional or Contractual Amount	387,714		291,243
Fair value	17,541		9,408
Net Exposure	17,541	[2]	9,408	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Foreign exchange forwards | Other liability
Derivative [Line Items]
Notional or Contractual Amount	366,835		267,218
Fair Value	(16,346)		(8,505)
Net Exposure	(16,346)	[2]	(8,505)	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Foreign currency options | Other assets
Derivative [Line Items]
Notional or Contractual Amount	75,600		118,133
Fair value	271		1,482
Net Exposure	271	[2]	1,482	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Foreign currency options | Other liability
Derivative [Line Items]
Notional or Contractual Amount	75,600		118,133
Fair Value	(271)		(1,482)
Net Exposure	(271)	[2]	(1,482)	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Loan conversion options | Other assets
Derivative [Line Items]
Notional or Contractual Amount	14,063		10,175
Fair value	923		4,291
Net Exposure	923	[2]	4,291	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Client interest rate derivatives | Other assets
Derivative [Line Items]
Notional or Contractual Amount	39,713
Fair value	50
Net Exposure	50	[2]
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives | Client interest rate derivatives | Other liability
Derivative [Line Items]
Notional or Contractual Amount	39,713
Fair Value	(52)
Net Exposure	$ (52)	[2]

[1] Cash collateral received from counterparties for our interest rate swap agreements is recorded as a component of "Short-term borrowings" on our consolidated balance sheets.

[2] Net exposure for contracts in a gain position reflects the replacement cost in the event of nonperformance by all such counterparties. The credit ratings of our institutional counterparties as of December 31, 2011 remain at investment grade or higher and there were no material changes in their credit ratings for the year ended December 31, 2011.