XML 46 R37.htm IDEA: XBRL DOCUMENT
v3.24.1

Fair Value Measurements - Measurement (Details) | Dec. 31, 2023 Y $ / shares item | Dec. 13, 2023 $ / shares | Nov. 14, 2023 $ / shares | Oct. 11, 2023 $ / shares | Sep. 30, 2023 $ / shares | Jun. 09, 2023 $ / shares | Dec. 31, 2022 $ / shares Y item
--- | --- | --- | --- | --- | --- | --- | ---
Common stock price |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input |  | 10.62 | 10.60 | 10.57 | 10.56 | 10.54 |
Risk-free rate |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input |  | 4.88 | 5.17 | 5.31 | 5.39 | 5.10 |
Volatility |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input |  | 65.52 | 63.91 | 64.90 | 65.96 | 76.56 |
Private placement warrants | Common stock price |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | 10.64 |  |  |  |  |  | 10.18
Private placement warrants | Exercise price |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | 11.50 |  |  |  |  |  | 11.50
Private placement warrants | Risk-free rate |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | item | 0.0381 |  |  |  |  |  | 0.0395
Private placement warrants | Volatility |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | item | 0.0000 |  |  |  |  |  | 0.0000
Private placement warrants | Term |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | Y | 5.21 |  |  |  |  |  | 5.25
Private placement warrants | Warrant to buy one share (adjusted for the probability of dissolution) |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | 0.03 |  |  |  |  |  | 0.02
Private placement warrants | Dividend yield |  |  |  |  |  |  |
Fair Value Measurement Inputs |  |  |  |  |  |  |
Measurement input | item | 0.0000 |  |  |  |  |  | 0.0000

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_MeasurementInputTypeAxis=us-gaap_MeasurementInputSharePriceMember
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=us-gaap_MeasurementInputPriceVolatilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=port_PrivatePlacementWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExercisePriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExpectedTermMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputConversionPriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExpectedDividendRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |