Business Combinations (Details) (USD $)	9 Months Ended			1 Months Ended	9 Months Ended			1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2011	Jul. 31, 2012 Rochdale Investment Management, LLC	Sep. 30, 2012 Rochdale Investment Management, LLC	Jul. 02, 2012 Rochdale Investment Management, LLC	Jul. 02, 2012 Rochdale Investment Management, LLC Client Contract	Apr. 30, 2012 First American Equipment Finance	Jun. 30, 2011 Nevada Commerce Bank	Sep. 30, 2012 Nevada Commerce Bank Y	Apr. 08, 2011 Nevada Commerce Bank
Business acquisitions
Assets under management by acquired firm, Rochdale Investment Management, LLC						$ 4,890,000,000
Carrying value of assets acquired								343,000,000			138,900,000
Carrying value of liabilities assumed								325,000,000			121,900,000
Fair value of acquired lease receivables								318,300,000
Borrowings and nonrecourse debt								320,900,000
Acquired goodwill						85,500,000		68,400,000
Customer contract intangible							19,000,000
Recognized contingent consideration liability at fair value						45,800,000
Low-end of the potential range of estimate of total consideration payment						32,000,000
High-end of the potential range of estimate of total consideration payment						74,000,000
Period of additional cash consideration payment				6 years
Acquisition related expense					2,000,000			600,000
Covered loans	55,313,000										56,400,000
Covered other real estate owned	7,463,000										7,500,000
Deposits	(126,795,000)										118,400,000
Cash from the FDIC											2,700,000
Gain on acquisition	8,164,000								8,200,000
FDIC reimbursement (as a percent)										80.00%
Term of loss-sharing agreements for single family residential loans (in years)										10
Term of loss-sharing agreements for other loans (in years)										8
FDIC indemnification asset		$ 160,991,000	$ 204,259,000								$ 33,800,000