Agreement and Plan of Merger (Narrative) (Details) - First Priority Financial Corp. [Member] $ in Billions	Jan. 16, 2018 USD ($)
Business Acquisition [Line Items]
Plan of merger agreement, date	Jan. 16, 2018
Business acquisition, proforma assets	$ 2
Shares of acquirer ratio of common stock	34.81%

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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