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Lease Accounting (Narrative) (Details)	3 Months Ended
	Mar. 31, 2021 contract superfundSites
Lessee, Lease, Description [Line Items]
Number of leases with restrictive covenants | superfundSites	102
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Lease renewal term	5 years
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	35 years
Lease renewal term	20 years
Land
Lessee, Lease, Description [Line Items]
Number of leases	392
Terminal
Lessee, Lease, Description [Line Items]
Number of leases	1
Office Building
Lessee, Lease, Description [Line Items]
Number of leases	1
Hangar
Lessee, Lease, Description [Line Items]
Number of leases	1

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- Definition

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- Definition

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- Definition

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- 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.

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No definition available.

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