Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details) (USD $)																		9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2014 Imperial Capital Bank	Dec. 31, 2013 Imperial Capital Bank	Sep. 30, 2014 1st Pacific Bank of California	Dec. 31, 2013 1st Pacific Bank of California	Sep. 30, 2014 Sun West Bank	Dec. 31, 2013 Sun West Bank	Sep. 30, 2014 Nevada Commerce Bank	Dec. 31, 2013 Nevada Commerce Bank	Sep. 30, 2014 Commercial	Dec. 31, 2013 Commercial	Dec. 31, 2013 Commercial Loans previously reported as lease financing	Sep. 30, 2014 Commercial Imperial Capital Bank	Sep. 30, 2014 Commercial 1st Pacific Bank of California	Sep. 30, 2014 Commercial Sun West Bank	Sep. 30, 2014 Commercial Nevada Commerce Bank	Sep. 30, 2014 Commercial real estate mortgages	Jun. 30, 2014 Commercial real estate mortgages	Dec. 31, 2013 Commercial real estate mortgages	Sep. 30, 2013 Commercial real estate mortgages	Jun. 30, 2013 Commercial real estate mortgages	Dec. 31, 2012 Commercial real estate mortgages	Sep. 30, 2014 Residential mortgages	Jun. 30, 2014 Residential mortgages	Dec. 31, 2013 Residential mortgages	Sep. 30, 2013 Residential mortgages	Jun. 30, 2013 Residential mortgages	Dec. 31, 2012 Residential mortgages	Sep. 30, 2014 Real estate construction	Jun. 30, 2014 Real estate construction	Dec. 31, 2013 Real estate construction	Sep. 30, 2013 Real estate construction	Jun. 30, 2013 Real estate construction	Dec. 31, 2012 Real estate construction	Sep. 30, 2014 Home equity loans and lines of credit	Jun. 30, 2014 Home equity loans and lines of credit	Dec. 31, 2013 Home equity loans and lines of credit	Sep. 30, 2013 Home equity loans and lines of credit	Jun. 30, 2013 Home equity loans and lines of credit	Dec. 31, 2012 Home equity loans and lines of credit	Sep. 30, 2014 Installment	Jun. 30, 2014 Installment	Dec. 31, 2013 Installment	Sep. 30, 2013 Installment	Jun. 30, 2013 Installment	Dec. 31, 2012 Installment	Sep. 30, 2014 Lease financing	Dec. 31, 2013 Lease financing	Dec. 31, 2013 Lease financing Loans previously reported as lease financing
Accounts notes and loans receivable
Loans and leases, excluding covered loans	$ 19,347,988,000		$ 17,170,438,000	$ 16,566,133,000											$ 8,612,691,000	$ 7,562,300,000	$ 158,200,000					$ 3,565,188,000		$ 3,223,001,000	$ 3,077,183,000			$ 5,023,213,000		$ 4,554,311,000	$ 4,418,231,000			$ 585,232,000		$ 367,004,000	$ 380,489,000			$ 759,258,000		$ 709,344,000	$ 681,879,000			$ 178,803,000		$ 151,955,000	$ 152,107,000			$ 623,603,000	$ 602,523,000	$ (158,200,000)
Less: Allowance for loan and lease losses	(312,703,000)	(311,276,000)	(302,584,000)	(295,947,000)	(289,914,000)	(277,888,000)																(50,989,000)	(50,651,000)	(50,678,000)	(49,926,000)	(53,339,000)	(48,901,000)	(11,467,000)	(10,296,000)	(11,540,000)	(13,114,000)	(8,004,000)	(10,558,000)	(8,745,000)	(7,191,000)	(6,351,000)	(9,691,000)	(8,335,000)	(11,784,000)	(7,028,000)	(6,575,000)	(6,677,000)	(8,298,000)	(5,400,000)	(7,283,000)	(2,384,000)	(2,284,000)	(1,842,000)	(1,872,000)	(1,355,000)	(1,858,000)
Loans and leases, excluding covered loans, net	19,035,285,000		16,867,854,000
Covered loans	552,715,000		716,911,000				492,445,000	630,754,000	24,748,000	40,110,000	13,025,000	18,761,000	22,497,000	27,286,000	2,273,000	10,009,000						522,883,000		666,628,000				5,203,000		4,976,000				19,016,000		31,184,000				3,089,000		3,695,000				251,000		419,000
Less: Allowance for loan losses	(9,368,000)	(9,103,000)	(15,922,000)	(25,882,000)	(24,414,000)	(44,781,000)
Covered loans, net	543,347,000		700,989,000
Total loans and leases	19,900,703,000		17,887,349,000
Net loans and leases	19,578,632,000		17,568,843,000
Unamortized fees, net of deferred costs	800,000		2,300,000
FDIC indemnification asset	59,917,000		89,227,000				51,074,000		2,431,000		3,105,000		3,307,000
FDIC clawback liability	$ 14,524,000								$ 12,240,000		$ 2,131,000		$ 153,000
Sharing of recoveries with FDIC on expiration date (as a percent)																		80.00%	80.00%	80.00%	80.00%
Sharing of recoveries with FDIC on termination date (as a percent)																		80.00%	80.00%	80.00%	80.00%