Deferred tax asset valuation allowance percent.

No definition available.

Name:	msn_DeferredTaxAssetValuationAllowancePercent
Namespace Prefix:	msn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Federal tax liability payable duration.

+ References

No definition available.

+ Details

Name:	msn_FederalTaxLiabilityPayableDuration
Namespace Prefix:	msn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of installments for federal tax liability payable.

+ References

No definition available.

+ Details

Name:	msn_NumberOfInstallmentsForFederalTaxLiabilityPayable
Namespace Prefix:	msn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of installments of federal tax liability paid.

+ References

No definition available.

+ Details

Name:	msn_NumberOfInstallmentsOfFederalTaxLiabilityPaid
Namespace Prefix:	msn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of federal tax liability payable in final installment.

+ References

No definition available.

+ Details

Name:	msn_PercentageOfFederalTaxLiabilityPayableInFinalInstallment
Namespace Prefix:	msn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of federal tax liability payable in first five installments.

+ References

No definition available.

+ Details

Name:	msn_PercentageOfFederalTaxLiabilityPayableInFirstFiveInstallments
Namespace Prefix:	msn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of federal tax liability payable in seventh installment.

+ References

No definition available.

+ Details

Name:	msn_PercentageOfFederalTaxLiabilityPayableInSeventhInstallment
Namespace Prefix:	msn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of federal tax liability payable in sixth installment.

+ References

No definition available.

+ Details

Name:	msn_PercentageOfFederalTaxLiabilityPayableInSixthInstallment
Namespace Prefix:	msn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of net operation loss carry forwards utilization limit against taxable income.

+ References

No definition available.

+ Details

Name:	msn_PercentageOfNetOperationLossCarryForwardsUtilizationLimitAgainstTaxableIncome
Namespace Prefix:	msn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Schedule of income taxes.

+ References

No definition available.

+ Details

Name:	msn_ScheduleOfIncomeTaxesLineItems
Namespace Prefix:	msn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32537-109319

+ Details

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

- Definition

The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.Fact.3)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

+ Details

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

- Definition

Tax year being audited in the income tax examination, in YYYY format.

+ References

No definition available.

+ Details

Name:	us-gaap_IncomeTaxExaminationYearUnderExamination
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:gYearListItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.7)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32672-109319

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22663-107794

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 20
-Section 45
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123586238&loc=d3e38679-109324

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(9))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22658-107794

+ Details

Name:	us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32559-109319

+ Details

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

- Definition

A description of the limitations on the use of all operating loss carryforwards available to reduce future taxable income.

+ References

No definition available.

+ Details

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

- Definition

Amount of tax liability from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

+ Details

Name:	us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of tax liability from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act, classified as current.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

+ Details

Name:	us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of tax liability from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act, classified as noncurrent.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

+ Details

Name:	us-gaap_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiabilityNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_DomesticCountryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=us-gaap_EarliestTaxYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=us-gaap_LatestTaxYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Income Taxes - Additional Information (Detail)	3 Months Ended		9 Months Ended	12 Months Ended
Income Taxes - Additional Information (Detail)	Jun. 30, 2021 USD ($) installment	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2021 USD ($)
Schedule Of Income Taxes [Line Items]
Income (loss) of foreign subsidiaries before taxes	$ 18,000		$ 22,000
Deferred tax valuation allowance against assets, Percent	100.00%
Deferred tax valuation allowance against assets	$ 3,800,000
Provision for income tax expense	11,000	$ 6,300
Federal tax liability	$ 2,031,000			$ 2,031,000
Federal tax liability payable period	8 years			8 years
Federal tax liability, Current portion	$ 195,000			$ 195,000
Federal tax liability, Non-current portion	$ 1,836,000			$ 1,836,000
Percentage of federal tax liability payable in first five installments	8.00%			8.00%
Percentage of federal tax liability payable in sixth installment	15.00%			15.00%
Percentage of federal tax liability payable in seventh installment	20.00%			20.00%
Percentage of federal tax liability payable in final installment	25.00%			25.00%
Number of installments for federal tax liability payable \| installment	8
Number of installments of federal tax liability paid \| installment	3
U.S. federal
Schedule Of Income Taxes [Line Items]
Net operating loss carry forwards, amount	$ 12,200,000
Operating loss carryovers, limitations on use	At June 30, 2021, the Company had $12.2 million of U.S. federal net operating loss (“NOL”) carry forwards. These losses do not expire but are limited to utilization of 80% of taxable income in any one year.
Percentage of NOLs utilization limit against taxable income	80.00%
U.S. federal \| Earliest Tax Year
Schedule Of Income Taxes [Line Items]
Open tax years	2016
U.S. federal \| Latest Tax Year
Schedule Of Income Taxes [Line Items]
Open tax years	2021
States
Schedule Of Income Taxes [Line Items]
Net operating loss carry forwards, amount	$ 15,300,000
States \| Earliest Tax Year
Schedule Of Income Taxes [Line Items]
Open tax years	2015
States \| Latest Tax Year
Schedule Of Income Taxes [Line Items]
Open tax years	2021