Leases - Major Tenants - Additional Information (Detail)	9 Months Ended
Sep. 30, 2021 Property Lease Tenant	Sep. 30, 2020
Leases [Line Items]
Number of significant tenants \| Tenant	2
Subsidiaries of Global Partners LP (NYSE GLP) [Member]
Leases [Line Items]
Number of leased properties \| Property	150
Number of unitary leases guaranteed by the parent	3
Subsidiaries of Global Partners LP (NYSE GLP) [Member] \| Sales Revenue, Net [Member] \| Customer Concentration Risk [Member]
Leases [Line Items]
Lease revenue percentage	16.00%	16.00%
Subsidiaries of ARKO Corp. (NASDAQ: ARKO) [Member]
Leases [Line Items]
Number of leased properties \| Property	128
Number of unitary leases guaranteed by the parent	4
Subsidiaries of ARKO Corp. (NASDAQ: ARKO) [Member] \| Sales Revenue, Net [Member] \| Customer Concentration Risk [Member]
Leases [Line Items]
Lease revenue percentage	15.00%	15.00%
Apro, LLC (d/b/a United Oil) [Member]
Leases [Line Items]
Number of leased properties \| Property	77
Number Of Unitary Leases To Tenant	3
Apro, LLC (d/b/a United Oil) [Member] \| Sales Revenue, Net [Member] \| Customer Concentration Risk [Member]
Leases [Line Items]
Lease revenue percentage	11.00%	12.00%
Subsidiaries of Chestnut Petroleum Dist. Inc.[Member]
Leases [Line Items]
Number of leased properties \| Property	70
Number of unitary leases	2
Subsidiaries of Chestnut Petroleum Dist. Inc.[Member] \| Sales Revenue, Net [Member] \| Customer Concentration Risk [Member]
Leases [Line Items]
Lease revenue percentage	9.00%	10.00%
Number of leased properties guaranteed	52

Leases.

No definition available.

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- Definition

The aggregate number of properties currently being leased to subsidiaries of our tenant.

+ References

No definition available.

+ Details

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- Definition

The number of properties in the unitary lease that is guaranteed by the parent company, its principals and affiliates.

+ References

No definition available.

+ Details

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- Definition

The number of current tenants that are considered significant.

+ References

No definition available.

+ Details

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- Definition

The number of unitary leases with subsidiaries of the tenant's parent.

+ References

No definition available.

+ Details

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- Definition

The number of unitary leases that are guaranteed by the parent company.

+ References

No definition available.

+ Details

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- Definition

The number of unitary leases leased to tenant.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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