Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 2) (USD $)	3 Months Ended
	Mar. 31, 2012 D	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Nevada Commerce Bank	Apr. 08, 2011 Nevada Commerce Bank	Mar. 31, 2012 Commercial	Dec. 31, 2011 Commercial	Mar. 31, 2012 Commercial real estate mortgages	Dec. 31, 2011 Commercial real estate mortgages	Mar. 31, 2012 Residential mortgage	Dec. 31, 2011 Residential mortgage	Mar. 31, 2012 Real estate construction	Dec. 31, 2011 Real estate construction	Mar. 31, 2012 Equity lines of credit	Dec. 31, 2011 Equity lines of credit	Mar. 31, 2012 Installment loan	Dec. 31, 2011 Installment loan
Accounts notes and loans receivable
Covered loans	$ 1,397,156,000		$ 1,481,854,000				$ 22,395,000	$ 30,911,000	$ 1,219,923,000	$ 1,288,352,000	$ 13,378,000	$ 14,931,000	$ 135,065,000	$ 140,992,000	$ 5,210,000	$ 5,167,000	$ 1,185,000	$ 1,501,000
Less: Allowance for loan losses	(61,471,000)	(82,016,000)	(64,565,000)	(67,389,000)
Covered loans, net of allowance for loan losses	1,335,685,000		1,417,289,000
Acquired loans
Preliminary estimates of the contractually required payments receivable for all acquired impaired covered loans					107,400,000
Cash flows expected to be collected					66,200,000
Fair value of acquired impaired loans					55,300,000
FDIC indemnification asset	185,392,000		204,259,000			33,800,000
Number of days of delinquency required to charge-off overdrafts	60
Number of days of delinquency required to charge-off secured consumer loans	180
Changes in Accretable Yield for Acquired Impaired Loans
Balance at the beginning of the period	436,374,000	562,826,000
Accretion	(22,225,000)	(27,572,000)
Reclassifications from (to) nonaccretable yield	(21,468,000)	(2,448,000)
Disposals and other	(16,213,000)	(11,248,000)
Balance at the end of the period	$ 376,468,000	$ 521,558,000