Contribution as credit against lease payments.

No definition available.

Name:	mchx_ContributionAsCreditAgainstLeasePayments
Namespace Prefix:	mchx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contribution from lessor as reimbursement towards leasehold improvements.

+ References

No definition available.

+ Details

Name:	mchx_ContributionFromLessorAsReimbursementTowardsLeaseholdImprovements
Namespace Prefix:	mchx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Lease commencement period.

+ References

No definition available.

+ Details

Name:	mchx_LeaseCommencementPeriod
Namespace Prefix:	mchx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Lease Termination month and year.

+ References

No definition available.

+ Details

Name:	mchx_LeaseTerminationMonthAndYear
Namespace Prefix:	mchx_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Payments for lease termination fee.

+ References

No definition available.

+ Details

Name:	mchx_PaymentsForLeaseTerminationFee
Namespace Prefix:	mchx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Date which lease or group of leases is set to expire, in YYYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Description of lessee's operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980

+ Details

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

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

Amount of increase (decrease) of the credit facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Name:	us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow for the allowance granted to lessee and/or direct costs incurred by lessor used to prepare the leased premises for tenant's occupancy.

+ References

No definition available.

+ Details

Name:	us-gaap_PaymentsForTenantImprovements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_StatementGeographicalAxis=mchx_MississaugaCanadaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=mchx_WichitaKansasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
Leases - Additional Information (Detail) - USD ($)	Apr. 30, 2019	Jun. 30, 2019	Mar. 31, 2018	Sep. 30, 2021	Apr. 30, 2018
Lessee Lease Description [Line Items]
Lease expiration date				Mar. 31, 2025
Payments for lease termination fee				$ 671,000
Contribution as credit against lease payments				$ 180,000
Contribution from lessor as reimbursement towards leasehold improvements		$ 180,000
Payments towards leasehold improvements			$ 373,000
Letter of credit amount payable					$ 575,000
Line of credit facility increase decrease for period net	$ 100,000
Lease termination month and year				2023-03
Mississauga, Canada
Lessee Lease Description [Line Items]
Lease expiration date				Nov. 30, 2021
Lease commencement period				November 2016
Lease term (in months)				60 months
Wichita, Kansas
Lessee Lease Description [Line Items]
Lease agreement description				The Company commenced a new lease for an office space in Wichita, Kansas in June 2020 which continues for a period of 66 months with an option to extend the term for two additional periods of three years each.