Fair Value Of Financial Instruments (Schedule Of Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale	$ 10,300
Securities purchased under agreements to resell	700,000	$ 700,000
Interest earning deposits with banks	334,752	30,631
Cash and due from banks	443,004	438,439
Derivative Assets	13,203	8,349
Assets held in trust for deferred compensation plan	14,384	12,843
Non-interest bearing deposits	6,728,605	7,158,962
Savings, interest checking and money market deposits	11,733,057	11,499,620
Other Borrowings	1,534	1,758
Derivative Liabilities	23,012	8,074
Liabilities held in trust for deferred compensation plan	14,384	12,843
Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	0	0
Assets held in trust for deferred compensation plan	14,384	12,843
Derivative Liabilities	0	0
Liabilities held in trust for deferred compensation plan	14,384	12,843
Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	12,500	7,723
Assets held in trust for deferred compensation plan	0	0
Derivative Liabilities	22,954	7,951
Liabilities held in trust for deferred compensation plan	0	0
Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Assets	703	626
Assets held in trust for deferred compensation plan	0	0
Derivative Liabilities	58	123
Liabilities held in trust for deferred compensation plan	0	0
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,955,559	13,983,674
Loans held for sale	16,890	21,398
Investments, Fair Value Disclosure	8,826,249	8,893,307
Federal funds sold	14,375	42,775
Securities purchased under agreements to resell	700,000	700,000
Interest earning deposits with banks	334,752	30,631
Cash and due from banks	443,004	438,439
Derivative Assets	13,203	8,349
Assets held in trust for deferred compensation plan	14,384	12,843
Assets, Fair Value Disclosure	24,318,416	24,131,416
Non-interest bearing deposits	6,728,605	7,158,962
Savings, interest checking and money market deposits	11,733,057	11,499,620
Time open and certificates of deposits	1,671,958	1,766,864
Federal Funds Purchased, Fair Value Disclosure	358,940	202,370
SecuritiesSold under Agreements to Repurchase, Fair Value Disclosure	1,503,177	1,304,768
Other Borrowings	1,534	1,758
Derivative Liabilities	23,012	8,074
Liabilities held in trust for deferred compensation plan	14,384	12,843
Financial Liabilities Fair Value Disclosure	22,034,667	21,955,259
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,966,722	4,958,554
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	999,691	968,820
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,726,042	2,697,452
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,120,672	2,062,787
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,967,465	2,104,487
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	375,322	400,587
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	788,111	783,864
Carrying (Reported) Amount, Fair Value Disclosure [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	11,534	7,123
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,639,972	13,993,509
Loans held for sale	16,890	21,398
Investments, Fair Value Disclosure	8,826,249	8,893,307
Federal funds sold	14,375	42,775
Securities purchased under agreements to resell	677,352	695,194
Interest earning deposits with banks	334,752	30,631
Cash and due from banks	443,004	438,439
Derivative Assets	13,203	8,349
Assets held in trust for deferred compensation plan	14,384	12,843
Assets, Fair Value Disclosure	23,980,181	24,136,445
Non-interest bearing deposits	6,728,605	7,158,962
Savings, interest checking and money market deposits	11,733,057	11,499,620
Time open and certificates of deposits	1,670,416	1,768,780
Federal Funds Purchased, Fair Value Disclosure	358,940	202,370
SecuritiesSold under Agreements to Repurchase, Fair Value Disclosure	1,504,560	1,305,375
Other Borrowings	1,534	1,758
Derivative Liabilities	23,012	8,074
Liabilities held in trust for deferred compensation plan	14,384	12,843
Financial Liabilities Fair Value Disclosure	22,034,508	21,957,782
Estimate of Fair Value, Fair Value Disclosure [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,865,676	4,971,401
Estimate of Fair Value, Fair Value Disclosure [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	995,910	979,389
Estimate of Fair Value, Fair Value Disclosure [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,685,924	2,702,598
Estimate of Fair Value, Fair Value Disclosure [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,046,763	2,060,443
Estimate of Fair Value, Fair Value Disclosure [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,937,606	2,074,129
Estimate of Fair Value, Fair Value Disclosure [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	368,218	400,333
Estimate of Fair Value, Fair Value Disclosure [Member] \| Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	731,363	798,093
Estimate of Fair Value, Fair Value Disclosure [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	8,512	7,123
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Loans held for sale	0	0
Investments, Fair Value Disclosure	903,880	937,011
Federal funds sold	14,375	42,775
Securities purchased under agreements to resell	0	0
Interest earning deposits with banks	334,752	30,631
Cash and due from banks	443,004	438,439
Derivative Assets	0	0
Assets held in trust for deferred compensation plan	14,384	12,843
Assets, Fair Value Disclosure	1,710,395	1,461,699
Non-interest bearing deposits	6,728,605	7,158,962
Savings, interest checking and money market deposits	11,733,057	11,499,620
Time open and certificates of deposits	0	0
Federal Funds Purchased, Fair Value Disclosure	358,940	202,370
SecuritiesSold under Agreements to Repurchase, Fair Value Disclosure	0	0
Other Borrowings	0	0
Derivative Liabilities	0	0
Liabilities held in trust for deferred compensation plan	14,384	12,843
Financial Liabilities Fair Value Disclosure	18,834,986	18,873,795
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 1 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Loans held for sale	16,890	21,398
Investments, Fair Value Disclosure	7,778,818	7,838,522
Federal funds sold	0	0
Securities purchased under agreements to resell	0	0
Interest earning deposits with banks	0	0
Cash and due from banks	0	0
Derivative Assets	12,500	7,723
Assets held in trust for deferred compensation plan	0	0
Assets, Fair Value Disclosure	7,808,208	7,867,643
Non-interest bearing deposits	0	0
Savings, interest checking and money market deposits	0	0
Time open and certificates of deposits	0	0
Federal Funds Purchased, Fair Value Disclosure	0	0
SecuritiesSold under Agreements to Repurchase, Fair Value Disclosure	0	0
Other Borrowings	0	0
Derivative Liabilities	22,954	7,951
Liabilities held in trust for deferred compensation plan	0	0
Financial Liabilities Fair Value Disclosure	22,954	7,951
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 2 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,639,972	13,993,509
Loans held for sale	0	0
Investments, Fair Value Disclosure	143,551	117,774
Federal funds sold	0	0
Securities purchased under agreements to resell	677,352	695,194
Interest earning deposits with banks	0	0
Cash and due from banks	0	0
Derivative Assets	703	626
Assets held in trust for deferred compensation plan	0	0
Assets, Fair Value Disclosure	14,461,578	14,807,103
Non-interest bearing deposits	0	0
Savings, interest checking and money market deposits	0	0
Time open and certificates of deposits	1,670,416	1,768,780
Federal Funds Purchased, Fair Value Disclosure	0	0
SecuritiesSold under Agreements to Repurchase, Fair Value Disclosure	1,504,560	1,305,375
Other Borrowings	1,534	1,758
Derivative Liabilities	58	123
Liabilities held in trust for deferred compensation plan	0	0
Financial Liabilities Fair Value Disclosure	3,176,568	3,076,036
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,865,676	4,971,401
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Real Estate - Construction And Land [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	995,910	979,389
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Real Estate - Business [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,685,924	2,702,598
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Real Estate - Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,046,763	2,060,443
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Consumer [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,937,606	2,074,129
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Revolving Home Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	368,218	400,333
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Credit Card [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	731,363	798,093
Estimate of Fair Value, Fair Value Disclosure [Member] \| Fair Value Hierarchy, Level 3 [Member] \| Overdrafts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	$ 8,512	$ 7,123

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

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

- Definition

For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

+ References

+ Details

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

- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

+ Details

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

- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313

+ Details

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

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

+ Details

Name:	us-gaap_DerivativeLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

+ References

+ Details

Name:	us-gaap_FederalFundsPurchasedFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements.

+ References

+ Details

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

- Definition

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancialLiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate of all domestic and foreign interest-bearing deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestBearingDepositLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.2)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=73530178&loc=d3e59706-112781

+ Details

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

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24584-111560

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

+ Details

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

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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

- Definition

The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

+ References

+ Details

Name:	us-gaap_NoninterestBearingDepositLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

+ References

+ Details

Name:	us-gaap_OtherBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

+ Details

Name:	us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after the effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes purchases of participations in pools of securities that are subject to a resale agreement, assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(2)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=49176635&loc=d3e9760-107771

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(3))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Amount of time deposit liabilities, including certificates of deposit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=50488274&loc=d3e64164-112818

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Industry Guide
-Number 3
-Section V
-Paragraph D-E

+ Details

Name:	us-gaap_TimeDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: