Percentage of adjustment of exercise price of warrants based on market value and newly issued price.

No definition available.

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- Definition

Price of the entity's common stock which would be required to be attained to trigger the redemption of warrants.

+ References

No definition available.

+ Details

Name:	port_ClassOfWarrantOrRightRedemptionOfWarrantsOrRightsStockPriceTrigger
Namespace Prefix:	port_
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- Definition

Threshold number of specified consecutive trading days for stock price trigger considered for redemption of warrants.

+ References

No definition available.

+ Details

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Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
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- Definition

Threshold number of specified trading days for stock price trigger considered for redemption of warrants.

+ References

No definition available.

+ Details

Name:	port_ClassOfWarrantOrRightRedemptionOfWarrantsOrRightsThresholdTradingDays
Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold number of trading days before sending notice of redemption to warrant holders.

+ References

No definition available.

+ Details

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Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
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- Definition

Redemption price per share or per unit of warrants or rights outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	port_
Data Type:	dtr-types:perShareItemType
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- Definition

The maximum threshold period for filing registration statement after business combination, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	port_MaximumThresholdPeriodForFilingRegistrationStatementAfterBusinessCombination
Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum threshold period for registration statement to become effective after business combination, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	port_MaximumThresholdPeriodForRegistrationStatementToBecomeEffectiveAfterBusinessCombination
Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate gross proceeds as a threshold minimum percentage of total equity proceeds.

+ References

No definition available.

+ Details

Name:	port_PercentageOfGrossProceedsOnTotalEquityProceedsThresholdMinimum
Namespace Prefix:	port_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The threshold period for not to transfer, assign or sell any of the shares or warrants, after the completion of the initial business combination.

+ References

No definition available.

+ Details

Name:	port_ThresholdPeriodForNotToTransferAssignOrSellAnySharesOrWarrantsAfterCompletionOfInitialBusinessCombination
Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold trading days for calculating Market Value of shares.

+ References

No definition available.

+ Details

Name:	port_ThresholdTradingDaysForCalculatingMarketValue
Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The warrants exercisable term after the completion of a business combination, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	port_WarrantsAndRightsOutstandingExercisableTermAfterBusinessCombination
Namespace Prefix:	port_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of warrants or rights outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-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

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
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- Details

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- Details

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- Details

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Data Type:	na
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- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=port_PublicWarrantsMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=port_PrivatePlacementWarrantsMember
Namespace Prefix:
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Period Type:

Warrants (Details) - $ / shares	3 Months Ended	12 Months Ended
Warrants (Details) - $ / shares	Mar. 31, 2025	Dec. 31, 2024	Sep. 11, 2024	Apr. 08, 2024
Warrants
Class of warrant or right outstanding	23,200,000	23,200,000
Threshold maximum period for registration statement to become effective after business combination	60 days	60 days
Threshold trading days for calculating Market Value	20 days	20 days
Newly issued price (in dollars per share)	$ 9.2	$ 9.2
Threshold minimum percentage of gross proceeds on total equity proceeds (as a percent)	60.00%	60.00%
Adjustment of exercise price of warrants based on market value and newly issued price (as a percent)	115.00%	115.00%
Threshold period for not to transfer, assign or sell any of their shares or warrants after the completion of the initial business combination	30 days	30 days
Class A common stock
Warrants
Newly issued price (in dollars per share)	$ 9.2	$ 9.2
Number of shares issuable per warrant (in shares)				1
Redemption of warrants when price per share of Class A common stock equals or exceeds $18.00
Warrants
Stock price trigger for redemption of warrants (in dollars per share)	$ 18
Redemption price per warrant (in dollars per share)		$ 18
Threshold consecutive trading days for redemption of warrants	30 days	30 days
Adjustment of exercise price of warrants based on market value and newly issued price (as a percent)	180.00%	180.00%
Redemption of warrants when price per share of Class A common stock equals or exceeds $18.00 \| Class A common stock
Warrants
Threshold trading days for redemption of warrants		20 days
Threshold consecutive trading days for redemption of warrants		30 days
Redemption of Warrants when price per share of Class A common stock equals or exceeds $10.00
Warrants
Stock price trigger for redemption of warrants (in dollars per share)	$ 10	$ 10
Threshold number of trading days before sending notice of redemption to warrant holders	30 days	30 days
Redemption price per warrant (in dollars per share)	$ 0.1	$ 0.1
Threshold trading days for redemption of warrants	20 days	20 days
Threshold consecutive trading days for redemption of warrants	30 days	30 days
Redemption of Warrants when price per share of Class A common stock equals or exceeds $10.00 \| Class A common stock
Warrants
Stock price trigger for redemption of warrants (in dollars per share)	$ 10	$ 10
Redemption of Warrants when price per share of Class A common stock is less than $18.00
Warrants
Redemption price per warrant (in dollars per share)	$ 18
Redemption of Warrants when price per share of Class A common stock is less than $18.00 \| Class A common stock
Warrants
Threshold trading days for redemption of warrants	20 days
Threshold consecutive trading days for redemption of warrants	30 days
Public Warrants
Warrants
Class of warrant or right outstanding	11,500,000	11,500,000
Warrants exercisable term after the completion of a business combination	30 days	30 days
Term of warrants	5 years	5 years
Threshold maximum period for filing registration statement after business combination	15 days	15 days
Public Warrants \| Class A common stock
Warrants
Number of shares issuable per warrant (in shares)			0.1
Public Warrants \| Redemption of warrants when price per share of Class A common stock equals or exceeds $18.00
Warrants
Stock price trigger for redemption of warrants (in dollars per share)	$ 18	$ 18
Threshold number of trading days before sending notice of redemption to warrant holders	30 days	30 days
Redemption price per warrant (in dollars per share)	$ 0.01	$ 0.01
Threshold trading days for redemption of warrants	20 days	20 days
Threshold consecutive trading days for redemption of warrants	30 days	30 days
Public Warrants \| Redemption of warrants when price per share of Class A common stock equals or exceeds $18.00 \| Class A common stock
Warrants
Stock price trigger for redemption of warrants (in dollars per share)	$ 18	$ 18
Private placement warrants
Warrants
Class of warrant or right outstanding	11,700,000	11,700,000