XML 76 R60.htm IDEA: XBRL DOCUMENT v3.20.4

Loans And Allowance For Credit Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Loans And Allowance For Loan Losses [Line Items]
Total loans	[1]	$ 16,329,641	$ 14,737,817
Interest Receivable		41,900
Commercial Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Accrued Interest Receivable on Held for Investment Loans, Write Off		329
Personal Banking Portfolio Segment [Member]
Loans And Allowance For Loan Losses [Line Items]
Accrued Interest Receivable on Held for Investment Loans, Write Off		5,700
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		6,546,087	5,565,449
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		1,021,595	899,377
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		3,026,117	2,833,554
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		2,820,030	2,354,760
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		1,950,502	1,964,145
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		307,083	349,251
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		655,078	764,977
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans		$ 3,149	$ 6,304
[1] (1) Accrued interest receivable totaled $41.9 million at December 31, 2020 and was included within other assets on the consolidated balance sheet. For the year ended December 31, 2020, the Company wrote-off accrued interest by reversing interest income of $329 thousand and $5.7 million in the Commercial and Personal Banking portfolios, respectively.

X

- Definition

Amount of interest receivable on held for investment loans that has been written off.

+ References

No definition available.

+ Details

Name:	cbsh_AccruedInterestReceivableOnHeldForInvestmentLoansWriteOff
Namespace Prefix:	cbsh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Loans And Allowance For Loan Losses [Line Items]

+ References

No definition available.

+ Details

Name:	cbsh_LoansAndAllowanceForLoanLossesLineItems
Namespace Prefix:	cbsh_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_InterestReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=cbsh_PersonalBankingPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_BusinessLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_ConstructionAndLandLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_BusinessRealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_PersonalRealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CreditCardReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cbsh_OverdraftsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: