Represents the period of the agreement under which the entity operates surface parking and garage parking spaces.

No definition available.

Name:	sp_AgreementPeriodForOperationOfParkingSpaces
Namespace Prefix:	sp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of annual guaranteed minimum payments.

+ References

No definition available.

+ Details

Name:	sp_AnnualGuaranteedMinimumPayments
Namespace Prefix:	sp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	sp_CompensationAbstract
Namespace Prefix:	sp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of accrued estimated deficiency payments that have met the criteria of being both probable and estimable during the period.

+ References

No definition available.

+ Details

Name:	sp_EstimatedAccruedDeficiencyPayments
Namespace Prefix:	sp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the management fees recognized during the period.

+ References

No definition available.

+ Details

Name:	sp_ManagementFees
Namespace Prefix:	sp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the maximum percentage of premium on deficiency payments previously made, which the entity has a right to receive.

+ References

No definition available.

+ Details

Name:	sp_MaximumPremiumPercentageOnInitialDeficiencyPayment
Namespace Prefix:	sp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of garage parking spaces operated by the entity.

+ References

No definition available.

+ Details

Name:	sp_NumberOfGarageParkingSpacesOperated
Namespace Prefix:	sp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of management fee apportioned to the entity as per the agreement.

+ References

No definition available.

+ Details

Name:	sp_PercentageOfManagementFeeApportionedToEntity
Namespace Prefix:	sp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of management fee apportioned to an un-affiliated entity as per the agreement.

+ References

No definition available.

+ Details

Name:	sp_PercentageOfManagementFeeApportionedToUnaffiliatedEntity
Namespace Prefix:	sp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of annual principal and interest payments on revenue bonds.

+ References

No definition available.

+ Details

Name:	sp_RevenueBondsAnnualPrincipalAndInterestPayments
Namespace Prefix:	sp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of cumulative management fees which have not been recognized.

+ References

No definition available.

+ Details

Name:	sp_UnrecognizedCumulativeManagementFees
Namespace Prefix:	sp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_TypeOfArrangementAxis=sp_BradleyInternationalAirportParkingFacilitiesOperatingAgreementMember
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_LongtermDebtTypeAxis=us-gaap_MunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Bradley Agreement - Narrative (Details)	12 Months Ended
Bradley Agreement - Narrative (Details)	Dec. 31, 2019 USD ($) parking_space	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2002 USD ($)
Compensation
Management fees	$ 0	$ 0	$ 0
Bradley International Airport parking facilities operating agreement
Agreement
Agreement period with the State of Connecticut for operation of parking spaces	25 years
Number of garage parking spaces at Bradley International Airport operated \| parking_space	3,500
Annual minimum guaranteed payment to the State by the trustee	$ 12,000,000.0	11,800,000
Maximum premium percentage on initial deficiency payment (not more than)	10.00%
Estimated accrued deficiency payments	$ 0	0
Compensation
Management fee apportioned to the entity (in percentage)	60.00%
Management fee apportioned to an un-affiliated entity (in percentage)	40.00%
Unrecognized cumulative management fees	$ 19,700,000	$ 18,700,000
Bradley International Airport parking facilities operating agreement \| Minimum
Agreement
Annual minimum guaranteed payment to the State by the trustee				$ 8,300,000
Bradley International Airport parking facilities operating agreement \| Maximum
Agreement
Annual minimum guaranteed payment to the State by the trustee	13,200,000
Bradley International Airport parking facilities operating agreement \| State of Connecticut special facility revenue bonds \| Minimum
Agreement
Annual principal and interest on revenue bonds				$ 3,600,000
Bradley International Airport parking facilities operating agreement \| State of Connecticut special facility revenue bonds \| Maximum
Agreement
Annual principal and interest on revenue bonds	$ 4,500,000