Parent Company Condensed Financial Statements (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 24, 2024
Investments in marketable common and preferred stock	$ 5,723	$ 6,210
Equity Securities without Readily Determinable Fair Value, Amount	6,978	6,094
Visa Class B-1 Shares | Subsequent Event [Member]
Equity Securities without Readily Determinable Fair Value, Share Class Redenomination				823,447
Commerce Bancshares, Inc. (Parent) [Member]
Note receivable due from bank subsidiary	50,000	50,000
Parent's line of credit facility with the Bank, maximum borrowing capacity	20,000
Parent line of credit with Bank, borrowings during period	0	$ 0	$ 0
Private Equity Investments, planned additional investments	69,400
Financial Instruments Owned Corporate Bonds	5,100
Investments in marketable common and preferred stock	5,400
Equity Securities without Readily Determinable Fair Value, Amount	$ 6,000