Disposal group, including discontinued operation, accounts payable and other.

No definition available.

Name:	merc_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndOther
Namespace Prefix:	merc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Disposal Group Including Discontinued Operation Impact Of Changes In Foreign Exchange Rate

No definition available.

Name:	merc_DisposalGroupIncludingDiscontinuedOperationImpactOfChangesInForeignExchangeRate
Namespace Prefix:	merc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Disposal group, including discontinued operation loss recognized on classification as held for sale.

No definition available.

Name:	merc_DisposalGroupIncludingDiscontinuedOperationLossRecognizedOnClassificationAsHeldForSale
Namespace Prefix:	merc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Disposal group, including discontinued operation operating lease liabilities.

No definition available.

Name:	merc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilities
Namespace Prefix:	merc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Disposal group, including discontinued operation operating lease right-of-use-assets.

No definition available.

Name:	merc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseRightOfUseAssets
Namespace Prefix:	merc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Disposal group, including discontinued operation sandalwood tree plantations.

No definition available.

Name:	merc_DisposalGroupIncludingDiscontinuedOperationSandalwoodTreePlantations
Namespace Prefix:	merc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount classified as assets attributable to disposal group held for sale or disposed of.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-SubTopic 20
-Topic 205
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483475/205-20-45-10

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-7

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5C
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5B
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483475/205-20-45-11

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

- References

No definition available.

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

Amount classified as accounts, notes and loans receivable attributable to disposal group held for sale or disposed of.

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

Amount classified as cash and cash equivalents attributable to disposal group held for sale or disposed of.

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

Amount classified as inventory attributable to disposal group held for sale or disposed of.

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationInventory1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount classified as prepaid and other assets attributable to disposal group held for sale or disposed of.

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

Amount classified as property, plant and equipment attributable to disposal group held for sale or disposed of.

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

Amount classified as liabilities attributable to disposal group held for sale or disposed of.

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

- References

No definition available.