Subsequent Events (Details) - The 2024 Credit Agreement - Subsequent Event	Aug. 07, 2024 USD ($)
Subsequent Event [Line Items]
Long-term debt	$ 212,500,000
EBITDA ratio, maximum	3.75
Permitted acquisitions	$ 50,000,000
Maximum EBITDA to interest expense ratio	300.00%
Leverage ratio minimum	2.50
Dividends payout	$ 100,000,000
Fed Funds Effective Rate Overnight Index Swap Rate
Subsequent Event [Line Items]
Basis spread on variable rate	0.50%
Adjusted Secured Overnight Financing Rate
Subsequent Event [Line Items]
Basis spread on variable rate	1.00%
Variable rate floor	1.00%
Adjusted Secured Overnight Financing Rate \| Minimum \| Variable Rate Component One
Subsequent Event [Line Items]
Basis spread on variable rate	0.25%
Adjusted Secured Overnight Financing Rate \| Minimum \| Variable Rate Component Two
Subsequent Event [Line Items]
Basis spread on variable rate	1.25%
Adjusted Secured Overnight Financing Rate \| Maximum \| Variable Rate Component One
Subsequent Event [Line Items]
Basis spread on variable rate	1.00%
Adjusted Secured Overnight Financing Rate \| Maximum \| Variable Rate Component Two
Subsequent Event [Line Items]
Basis spread on variable rate	2.00%
Adjusted Risk Free Rate \| Minimum
Subsequent Event [Line Items]
Basis spread on variable rate	1.25%
Adjusted Risk Free Rate \| Maximum
Subsequent Event [Line Items]
Basis spread on variable rate	2.00%
Revolving credit facility borrowings \| Line of Credit
Subsequent Event [Line Items]
Revolving credit facility	$ 650,000,000
Credit facility	$ 325,000,000
Revolving credit facility borrowings \| Minimum
Subsequent Event [Line Items]
Commitment fee (as a percent)	0.15%
Revolving credit facility borrowings \| Maximum
Subsequent Event [Line Items]
Commitment fee (as a percent)	0.30%

Debt Instrument, Covenant, EBITDA to Interest Expense Ratio, Maximum

No definition available.

Name:	tnc_DebtInstrumentCovenantEBITDAToInterestExpenseRatioMaximum
Namespace Prefix:	tnc_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Requirement for minimum leverage ratio required to pay dividends or repurchase stock under the debt agreement.

+ References

No definition available.

+ Details

Name:	tnc_DebtInstrumentCovenantMinimumLeverageRatioForDividendsOrRepurchaseOfStock
Namespace Prefix:	tnc_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum amount of permitted acquisition to have alternative requirements for the indebtedness to EBITDA ratio under the covenant of the debt instrument.

+ References

No definition available.

+ Details

Name:	tnc_DebtInstrumentCovenantMinimumPermittedAcquisitionAlternativeRequirementsForIndebtednessToEBITDARatio
Namespace Prefix:	tnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The maximum senior secured net indebtedness to adjusted EBITDA ratio allowed under the covenant of the debt instrument.

+ References

No definition available.

+ Details

Name:	tnc_DebtInstrumentCovenantSeniorSecuredNetIndebtednessToAdjustedEBITDARatioMaximum
Namespace Prefix:	tnc_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum amount of dividends payout or repurchase of stock allowed under the debt instrument.

+ References

No definition available.

+ Details

Name:	tnc_DebtInstrumentRestrictionsMaximumDividendsPayoutOrRepurchaseOfStock
Namespace Prefix:	tnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The floor rate of the variable rate of the debt instrument.

+ References

No definition available.

+ Details

Name:	tnc_DebtInstrumentVariableRateFloor
Namespace Prefix:	tnc_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of option to increase the maximum borrowing capacity of the line of credit facility.

+ References

No definition available.

+ Details

Name:	tnc_LineOfCreditFacilityAdditionalBorrowingsOption
Namespace Prefix:	tnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-4

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=tnc_The2024CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=tnc_AdjustedSecuredOvernightFinancingRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	tnc_VariableRateComponentAxis=tnc_VariableRateComponentOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	tnc_VariableRateComponentAxis=tnc_VariableRateComponentTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=tnc_AdjustedRiskFreeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: