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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The face amount of loans that will be sold to other entities.

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Organization (Details Textual)	12 Months Ended
Organization (Details Textual)	Dec. 31, 2018 USD ($) reportable_segment bank_branch	Dec. 31, 2017 USD ($) reportable_segment	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Loans Receivable Held-for-sale, Amount	$ 0	$ 1,500,000,000
Transfer of Portfolio Loans and Leases to Held-for-sale	0	481,100,000	$ 0
Loans held for sale, at lower of cost or fair value		481,100,000
Proceeds from Sale and Collection of Lease Receivables	0	$ 0	$ 138,955,000
Financing Receivable, Collectively Evaluated for Impairment	$ 17,865,646,000
Allowance For Credit Losses, Look-back Period for Estimation	40	31
Fair Value Hedges, Net	$ 0
Derivative, Notional Amount	$ 80,500,000
Number of Reportable Segments \| reportable_segment	1
Core Deposits [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Core Deposits [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Customer Relationships [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	4 years
Customer Relationships [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Furniture and Fixtures [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Furniture and Fixtures [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Building [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	30 years
Equity Securities [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	20.00%
Equity Securities [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Loans Under $250,000
Business Acquisition [Line Items]
Financing Receivable, Collectively Evaluated for Impairment	$ 250,000
CALIFORNIA
Business Acquisition [Line Items]
Retail Branch Locations \| bank_branch	74
NORTH CAROLINA
Business Acquisition [Line Items]
Retail Branch Locations \| bank_branch	1
Retained Earnings [Member]
Business Acquisition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (529,000)
Cash Flow [Member]
Business Acquisition [Line Items]
Proceeds from Sale of Loans Held-for-sale		$ 1,000,000,000
New ALLL Methodology (2018) [Member] \| Twenty-one (21) [Member]
Business Acquisition [Line Items]
Allowance for Credit Losses, Change in Method of Calculating Probable Credit Loss \| reportable_segment		21
Pre- 2018 ALLL Methodology (2018) [Member] \| Thirty-four (34) [Member]
Business Acquisition [Line Items]
Allowance for Credit Losses, Change in Method of Calculating Probable Credit Loss \| reportable_segment		34
Limited Partnership [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	5.00%
Accounting Standards Update 2018-02 [Member]
Business Acquisition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 6,665,000