INCOME TAXES - Schedule of Deferred Income Tax Balances (Detail) - USD ($) $ in Thousands	Jul. 31, 2020	Jul. 31, 2019
Income Tax Disclosure [Abstract]
Inventory basis	$ 1,000	$ 807
Employee benefits	7,353	5,272
Self-insurance reserves	4,923	5,185
Accrued product warranties	53,586	62,563
Accrued incentives	4,316	6,144
Sales returns and allowances	1,027	1,516
Accrued expenses	6,733	3,617
Property, plant and equipment	(28,438)	(22,699)
Operating leases	9,110	0
Deferred compensation	15,876	15,247
Intangibles	(147,423)	(143,861)
Net operating loss and other carryforwards	32,877	15,725
Unrealized (gain)/loss	4,892
Unrealized (gain)/loss		(4,546)
Unrecognized tax benefits	3,046	2,689
Other	4,558	2,759
Valuation allowance	(18,500)	(12,945)
Deferred income tax (liability), net	$ (45,064)	$ (62,527)

Deferred tax assets (liabilities), inventory.

No definition available.

Name:	tho_DeferredTaxAssetsLiabilitiesInventory
Namespace Prefix:	tho_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Deferred Tax Assets, Operating Leases

+ References

No definition available.

+ Details

Name:	tho_DeferredTaxAssetsOperatingLeases
Namespace Prefix:	tho_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Deferred tax assets, tax deferred expense accrued product warranties.

+ References

No definition available.

+ Details

Name:	tho_DeferredTaxAssetsTaxDeferredExpenseAccruedProductWarranties
Namespace Prefix:	tho_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Deferred tax assets unrecognized tax benefits non current.

+ References

No definition available.

+ Details

Name:	tho_DeferredTaxAssetsUnrecognizedTaxBenefitsNonCurrent
Namespace Prefix:	tho_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319

+ Details

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

- Definition

Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319

+ Details

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

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.

+ References

+ Details

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

- Definition

Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences from employee benefits, classified as other.

+ References

+ Details

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

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from employee compensation.

+ References

+ Details

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

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

+ References

+ Details

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

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from estimated returns and sales allowances.

+ References

+ Details

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

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from estimated losses under self insurance.

+ References

+ Details

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

- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses on foreign currency transactions.

+ References

+ Details

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

- 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=84230637&loc=d3e32537-109319

+ Details

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

- Definition

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=120406818&loc=d3e31931-109318

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

+ Details

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

- Definition

Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

+ References

+ Details

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

- Definition

Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

+ References

+ Details

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

- Definition

Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on foreign currency transactions.

+ References

+ Details

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

- References

No definition available.

+ Details

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