Changes in Carrying Amount of Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended		9 Months Ended
Sep. 30, 2012	Dec. 31, 2010	Sep. 30, 2012 Bank	Dec. 31, 2010 Bank	Sep. 30, 2012 Institutional Investment Management	Dec. 31, 2011 Institutional Investment Management	Dec. 31, 2010 Institutional Investment Management	Sep. 30, 2012 Asset Servicing	Dec. 31, 2011 Asset Servicing	Dec. 31, 2010 Asset Servicing
Goodwill And Other Intangible Assets [Line Items]
Beginning Balance	$ 211,114	$ 211,114	$ 144,109	$ 144,109	$ 47,529	$ 47,529	$ 47,529	$ 19,476	$ 19,476	$ 19,476
Goodwill disposals during period	(1,356)		(1,356)
Ending Balance	$ 209,758	$ 211,114	$ 142,753	$ 144,109	$ 47,529	$ 47,529	$ 47,529	$ 19,476	$ 19,476	$ 19,476

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

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