Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details) (USD $)																		6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2014 Imperial Capital Bank	Dec. 31, 2013 Imperial Capital Bank	Jun. 30, 2014 1st Pacific Bank of California	Dec. 31, 2013 1st Pacific Bank of California	Jun. 30, 2014 Sun West Bank	Dec. 31, 2013 Sun West Bank	Jun. 30, 2014 Nevada Commerce Bank	Dec. 31, 2013 Nevada Commerce Bank	Jun. 30, 2014 Commercial	Dec. 31, 2013 Commercial	Dec. 31, 2013 Commercial Loans previously reported as lease financing	Jun. 30, 2014 Commercial Imperial Capital Bank	Jun. 30, 2014 Commercial 1st Pacific Bank of California	Jun. 30, 2014 Commercial Sun West Bank	Jun. 30, 2014 Commercial Nevada Commerce Bank	Jun. 30, 2014 Commercial real estate mortgages	Mar. 31, 2014 Commercial real estate mortgages	Dec. 31, 2013 Commercial real estate mortgages	Jun. 30, 2013 Commercial real estate mortgages	Mar. 31, 2013 Commercial real estate mortgages	Dec. 31, 2012 Commercial real estate mortgages	Jun. 30, 2014 Residential mortgage	Mar. 31, 2014 Residential mortgage	Dec. 31, 2013 Residential mortgage	Jun. 30, 2013 Residential mortgage	Mar. 31, 2013 Residential mortgage	Dec. 31, 2012 Residential mortgage	Jun. 30, 2014 Real estate construction	Mar. 31, 2014 Real estate construction	Dec. 31, 2013 Real estate construction	Jun. 30, 2013 Real estate construction	Mar. 31, 2013 Real estate construction	Dec. 31, 2012 Real estate construction	Jun. 30, 2014 Home equity loans and lines of credit	Mar. 31, 2014 Home equity loans and lines of credit	Dec. 31, 2013 Home equity loans and lines of credit	Jun. 30, 2013 Home equity loans and lines of credit	Mar. 31, 2013 Home equity loans and lines of credit	Dec. 31, 2012 Home equity loans and lines of credit	Jun. 30, 2014 Installment	Mar. 31, 2014 Installment	Dec. 31, 2013 Installment	Jun. 30, 2013 Installment	Mar. 31, 2013 Installment	Dec. 31, 2012 Installment	Jun. 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	$ 18,474,788,000		$ 17,170,438,000	$ 15,819,252,000											$ 8,230,112,000	$ 7,562,300,000	$ 158,200,000					$ 3,464,918,000		$ 3,223,001,000	$ 2,978,975,000			$ 4,814,435,000		$ 4,554,311,000	$ 4,153,051,000			$ 457,557,000		$ 367,004,000	$ 340,002,000			$ 716,816,000		$ 709,344,000	$ 700,681,000			$ 183,518,000		$ 151,955,000	$ 149,438,000			$ 607,432,000	$ 602,523,000	$ (158,200,000)
Less: Allowance for loan and lease losses	(311,276,000)	(305,790,000)	(302,584,000)	(289,914,000)	(282,328,000)	(277,888,000)																(50,651,000)	(51,361,000)	(50,678,000)	(53,339,000)	(52,016,000)	(48,901,000)	(10,296,000)	(11,595,000)	(11,540,000)	(8,004,000)	(7,253,000)	(10,558,000)	(7,191,000)	(6,468,000)	(6,351,000)	(8,335,000)	(9,962,000)	(11,784,000)	(6,575,000)	(6,419,000)	(6,677,000)	(5,400,000)	(4,843,000)	(7,283,000)	(2,284,000)	(1,824,000)	(1,842,000)	(1,355,000)	(1,225,000)	(1,858,000)
Loans and leases, excluding covered loans, net	18,163,512,000		16,867,854,000
Covered loans	605,770,000		716,911,000				536,292,000	630,754,000	32,320,000	40,110,000	13,651,000	18,761,000	23,507,000	27,286,000	6,992,000	10,009,000						568,902,000		666,628,000				5,525,000		4,976,000				20,742,000		31,184,000				3,342,000		3,695,000				267,000		419,000
Less: Allowance for loan losses	(9,103,000)	(9,103,000)	(15,922,000)	(24,414,000)	(42,354,000)	(44,781,000)
Covered loans, net	596,667,000		700,989,000
Total loans and leases	19,080,558,000		17,887,349,000
Net loans and leases	18,760,179,000		17,568,843,000
Unamortized fees, net of deferred costs	1,100,000		2,300,000
FDIC indemnification asset	68,038,000		89,227,000				57,624,000		2,368,000		4,137,000		3,909,000
FDIC clawback liability	$ 14,079,000								$ 12,122,000		$ 1,925,000		$ 32,000
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%