Summary Of Significant Accounting And Reporting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) branch	Dec. 31, 2019 USD ($)
Condensed Financial Statements, Captions [Line Items]
Number of Reportable Segments	1
DiscontinuationofInterestThresholdDays	90 days
Financing Receivable, Threshold Period Past Due	30 days
Threshold period past due for write-off of financing receivable	120 days
Other real estate, foreclosed assets, and repossessed assets	$ 1,700	$ 4,700
Amortization Method Qualified Affordable Housing Project Investments	14,400	10,100
Qualified Affordable Housing Project Investments, Commitment	6,800	3,200
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	$ 0	$ 4,056
Repayment Price Junior Subordinated Deferrable Interest Debentures	100.00%
Subordinated Borrowing, Interest Rate		3.74%
City National
Condensed Financial Statements, Captions [Line Items]
Number of offices | branch	94