Acquisition of First Priority Financial Corp. (Preliminary Estimated Fair Value of Assets Acquired) (Details) - USD ($)	Jul. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Net assets acquired:
Goodwill		$ 62,840,000	$ 62,840,000
First Priority Financial Corp. [Member]
Business Acquisition [Line Items]
Total purchase price (consideration paid)	$ 79,929,000
Net assets acquired:
Cash and cash equivalents	11,398,000
Investment securities	62,977,000
Restricted stock	2,237,000
Loans	511,623,000
Core deposit intangible	2,832,000
Trade name intangible	205,000
Premises and equipment	1,147,000
Foreclosed assets	125,000
Deferred income taxes	3,140,000
Accrued interest receivable	2,293,000
Other assets	4,197,000
Deposits	(504,946,000)
Borrowings	(49,939,000)
Accrued interest payable	(1,073,000)
Other liabilities	(2,627,000)
Preferred stock	(3,404,000)
Total net assets acquired	40,185,000
Goodwill	$ 39,744,000