XML 47 R38.htm IDEA: XBRL DOCUMENT v3.24.1

Fair Value Measurements - Non-recurring Fair Value Measurements (Details)	May 25, 2023 USD ($) $ / shares shares	Dec. 31, 2023 shares	Dec. 13, 2023 $ / shares Y shares	Nov. 14, 2023 $ / shares Y shares	Oct. 11, 2023 Y $ / shares shares	Sep. 30, 2023 $ / shares Y shares	Jun. 09, 2023 Y $ / shares shares
Sponsor | Class B common stock
Fair Value Measurement Inputs
Shares transferred upon consummation of extension | shares	500,000						500,000
Fair value per share of shares transferred upon consummation of extension | $	$ 387,000
Fair value per share of shares transferred upon consummation of extension (in per shares)	$ 0.77
Additional non redemption shares transferred | shares	166,666	666,664	166,666	166,666	166,666	166,666
Sponsor | Class B common stock | Minimum
Fair Value Measurement Inputs
Fair value of common stock on additional shares transferred per share	$ 0.82
Sponsor | Class B common stock | Maximum
Fair Value Measurement Inputs
Fair value of common stock on additional shares transferred per share	$ 0.83
Common stock price
Fair Value Measurement Inputs
Measurement input			10.62	10.60	10.57	10.56	10.54
Estimated probability of an Initial Business Combination
Fair Value Measurement Inputs
Measurement input			10.00	10.00	10.00	10.00	10.00
Estimated volatility
Fair Value Measurement Inputs
Measurement input			65.52	63.91	64.90	65.96	76.56
Risk-free rate
Fair Value Measurement Inputs
Measurement input			4.88	5.17	5.31	5.39	5.10
Time to expiration
Fair Value Measurement Inputs
Measurement input | Y			1.00	1.00	1.00	1.00	1.00

X

- Definition

The additional non-redemption shares transferred.

+ References

No definition available.

+ Details

Name:	port_AdditionalNonRedemptionSharesTransferred
Namespace Prefix:	port_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Fair value per share of Additional shares transferred upon consummation of extension.

+ References

No definition available.

+ Details

Name:	port_FairValueOfCommonStockOnAdditionalSharesTransferredPerShare
Namespace Prefix:	port_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of excess fair value of common stock transferred by Sponsor in non-cash investing and financing activities.

+ References

No definition available.

+ Details

Name:	port_FairValueOfCommonStockTransferred
Namespace Prefix:	port_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Fair value per share of shares transferred upon consummation of extension.

+ References

No definition available.

+ Details

Name:	port_FairValueOfCommonStockTransferredPerShare
Namespace Prefix:	port_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of shares transferred to consummation of extension.

+ References

No definition available.

+ Details

Name:	port_SharesTransferredToConsummationOfExtension
Namespace Prefix:	port_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

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

X

- Definition

Value of input used to measure outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_WarrantsAndRightsOutstandingMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=port_SponsorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputSharePriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=port_MeasurementInputEstimatedProbabilityOfInitialBusinessCombinationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputPriceVolatilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputRiskFreeInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=port_TimeToExpirationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: