Debt - Debt (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total debt	$ 279,840	$ 198,669
Less current maturities	47,656	37,857
Long-term debt	232,184	$ 160,812
Revolving credit facility borrowing [Member]
Debt Instrument [Line Items]
Total debt	$ 6,000
Maturity Dates	2021	2021
Unsecured private placement 3.95% note [Member]
Debt Instrument [Line Items]
Total debt	$ 85,474	$ 99,727
Debt instrument interest rate percentage	3.95%	3.95%
Unsecured private placement 3.95% note [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2021	2021
Unsecured private placement 3.95% note [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2027	2027
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Total debt	$ 56,948	$ 71,193
Debt instrument interest rate percentage	3.86%	3.86%
Unsecured private placement 3.86% note [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2021	2021
Unsecured private placement 3.86% note [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2025	2025
Unsecured private placement 4.86% note [Member]
Debt Instrument [Line Items]
Total debt	$ 27,779	$ 27,749
Debt instrument interest rate percentage	4.86%	4.86%
Unsecured private placement 4.86% note [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2021	2021
Unsecured private placement 4.86% note [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2023	2023
Unsecured private placement 2.30% note [Member]
Debt Instrument [Line Items]
Total debt	$ 49,925
Debt instrument interest rate percentage	2.30%	2.30%
Unsecured private placement 2.30% note [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Unsecured private placement 2.30% note [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2028	2028
Unsecured private placement 2.37% note [Member]
Debt Instrument [Line Items]
Total debt	$ 49,915
Debt instrument interest rate percentage	2.37%	2.37%
Unsecured private placement 2.37% note [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Unsecured private placement 2.37% note [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2028	2028
Debt of foreign subsidiaries Unsecured bank debt, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	$ 3,799
Maturity Dates	2021	2021

Debt instruments maturity year.

No definition available.

Name:	scl_DebtInstrumentsMaturityYear
Namespace Prefix:	scl_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=scl_UnsecuredPrivatePlacementNotesOneMember
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:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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