Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Apr. 08, 2011 Nevada Commerce Bank	Dec. 31, 2010 Sun West Bank and 1st Pacific Bank of California	Dec. 31, 2011 Commercial	Dec. 31, 2010 Commercial	Dec. 31, 2011 Commercial real estate mortgages	Dec. 31, 2010 Commercial real estate mortgages	Dec. 31, 2011 Residential mortgage	Dec. 31, 2010 Residential mortgage	Dec. 31, 2011 Real estate construction	Dec. 31, 2010 Real estate construction	Dec. 31, 2011 Equity lines of credit	Dec. 31, 2010 Equity lines of credit	Dec. 31, 2011 Installment loan	Dec. 31, 2010 Installment loan
Accounts notes and loans receivable
Covered loans	$ 1,481,854,000	$ 1,857,522,000			$ 30,911,000	$ 55,082,000	$ 1,288,352,000	$ 1,569,739,000	$ 14,931,000	$ 18,380,000	$ 140,992,000	$ 204,945,000	$ 5,167,000	$ 6,919,000	$ 1,501,000	$ 2,457,000
Less: Allowance for loan losses	(64,565,000)	(67,389,000)
Covered loans, net of allowance for loan losses	1,417,289,000	1,790,133,000
Acquired loans
Preliminary estimates of the contractually required payments receivable for all acquired impaired covered loans			107,400,000	643,300,000
Cash flows expected to be collected			66,200,000	378,900,000
Fair value of acquired impaired loans			55,300,000	330,600,000
Fair value of acquired loans not accounted for as acquired impaired loans at acquisition date			1,100,000
FDIC indemnification asset	204,259,000	295,466,000	33,800,000
Changes in Accretable Yield for Acquired Impaired Loans
Balance at the beginning of the period	562,826,000	687,126,000
Additions	10,871,000	48,644,000
Accretion	(104,056,000)	(116,477,000)
Reclassifications to nonaccretable yield	33,704,000	(27,411,000)
Disposals and other	(66,971,000)	(29,056,000)
Balance at the end of the period	$ 436,374,000	$ 562,826,000