Amount of initial agreed contract price of a construction contract between the entity and the customer.

No definition available.

Name:	slnd_ConstructionContractPrice
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of retainage withheld under a construction contract, collectible upon completion or acceptance of work.

+ References

No definition available.

+ Details

Name:	slnd_ConstructionContractRetainageReceivable
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of claim under construction contract that is collectible and recorded as a contract asset.

+ References

No definition available.

+ Details

Name:	slnd_ContractAssetFromClaims
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of consideration claimed by the entity under the construction project, subject to resolution.

+ References

No definition available.

+ Details

Name:	slnd_ContractClaimValue
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Increase (decrease) in mount billed to customers under long-term contracts or programs that have been withheld because of retainage provisions in a contract.

+ References

No definition available.

+ Details

Name:	slnd_IncreaseDecreaseInRetainageReceivables
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Increase in the length of streetcar system previously constructed.

+ References

No definition available.

+ Details

Name:	slnd_IncreaseInLengthOfStreetcarSystemPreviouslyConstructed
Namespace Prefix:	slnd_
Data Type:	dtr-types:lengthItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase in cost of construction including non-cash charge due to adverse ruling in legal settlement.

+ References

No definition available.

+ Details

Name:	slnd_LegalSettlementAggregateIncreaseInCostOfConstruction
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of decrease in revenue due to adverse ruling in legal settlement.

+ References

No definition available.

+ Details

Name:	slnd_LegalSettlementDecreaseInRevenue
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase in cost of construction due to adverse ruling in legal settlement.

+ References

No definition available.

+ Details

Name:	slnd_LegalSettlementIncreaseInCostOfConstruction
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of litigation settlement accrued.

+ References

No definition available.

+ Details

Name:	slnd_LitigationSettlementLongTermAccruedLiability
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of a sanctions order awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

Name:	slnd_LitigationSettlementSanctionsOrderAwardedToOtherParty
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total amount of impact to consolidated statement of operations from adverse ruling in litigation.

+ References

No definition available.

+ Details

Name:	slnd_LitigationSettlementTotalImpact
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of non-cash charge to revenue.

+ References

No definition available.

+ Details

Name:	slnd_NonCashChargeToRevenue
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of derecognition of contract assets treated as non cash.

+ References

No definition available.

+ Details

Name:	slnd_NonCashDerecognitionOfContractAssets
Namespace Prefix:	slnd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The original length of streetcar system constructed as per the contract.

+ References

No definition available.

+ Details

Name:	slnd_OriginalLengthOfStreetcarSystemConstructed
Namespace Prefix:	slnd_
Data Type:	dtr-types:lengthItemType
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

+ Details

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

- Definition

The amount or range of possible amounts of gain that could be realized upon the resolution of a contingency.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483049/450-30-50-1

+ Details

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

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

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

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-10

+ Details

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

- Definition

The total number of new claims filed pertaining to a loss contingency during the period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

+ Details

Name:	us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=slnd_CityLynxGoldLinePhase2StreetcarProjectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=slnd_CityOfCharlotteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=us-gaap_PendingLitigationMember
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_CounterpartyNameAxis=slnd_ClarkLewisJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=slnd_WashingtonStateConventionCenterProjectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Narrative (Details) $ in Millions						12 Months Ended
	Dec. 12, 2025 USD ($)	Dec. 01, 2025 USD ($)	Apr. 12, 2023 claim	Mar. 17, 2018 USD ($)	Nov. 28, 2016 mi	Dec. 31, 2025 USD ($)	Jun. 11, 2024 USD ($)
City LYNX Gold Line Phase 2 Streetcar
Commitments and Contingencies
Original length of streetcar system constructed \| mi					1.5
Increase in length of streetcar system, previously constructed \| mi					2.5
City of Charlotte \| Pending Litigation
Commitments and Contingencies
Number of claims \| claim			10
City of Charlotte \| Pending Litigation \| Minimum
Commitments and Contingencies
Damages sought							$ 115.0
CLJV \| Washington State Convention Center Project
Commitments and Contingencies
Construction contract price				$ 81.4
Contract claim value				80.0
Contract asset from claims				40.3
Construction contract, Retainage receivable				6.4
Loss Contingency Accrual				$ 58.0
Litigation settlement, amount awarded to other party		$ 57.1
Sanctions order awarded to other party	$ 4.8
Non-cash charge to revenue		40.3
Non-cash reduction to contract assets		40.3
Long term accrued liability		89.1				$ 89.1
Decrease in retainage receivables		6.4				6.4
Decrease in revenue		46.7				6.4
Cost of construction		89.1
Total impact to consolidated statement of operations		$ 135.8
Increase in cost of construction						$ 89.1