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- Definition

Amount of allowance for credit losses related to receivables which had been measured under a general allowance for credit losses methodology that are now identified as troubled debt restructurings.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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- Definition

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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- Definition

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 number of businesses acquired by the entity during the period.

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Organization (Details Textual)	6 Months Ended	12 Months Ended
Organization (Details Textual)	Jun. 30, 2018 USD ($) acquisition bank_branch	Dec. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Allowance for Credit Losses, Change in Method of Calculating Impairment		$ 34	$ 21
Number of Businesses Acquired \| acquisition	29
CALIFORNIA
Business Acquisition [Line Items]
Retail Branch Locations \| bank_branch	74
NORTH CAROLINA
Business Acquisition [Line Items]
Retail Branch Locations \| bank_branch	1
Accounting Standards Update 2016-01
Business Acquisition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (529,000)
Accounting Standards Update 2018-02
Business Acquisition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 6,665,000
Equity Securities \| Minimum
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	20.00%
Equity Securities \| Maximum
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Purchased Credit Impaired Loans and Leases
Business Acquisition [Line Items]
Percentage of nonaccrual loans and leases		0.40%
Partnership Interest \| Minimum
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage	5.00%