Acquisitions - Narrative (Details) $ in Millions	3 Months Ended
Mar. 31, 2017 USD ($) acquisition	Mar. 31, 2016 acquisition airport
Aviation fueling operations of certain ExxonMobil affiliates
Acquisitions
Number of airports to be acquired (more than) \| airport		80
Acquisitions 2017
Acquisitions
Number of businesses acquired \| acquisition	2
Goodwill anticipated to be deductible for tax purposes \| $	$ 25.9
Acquisitions 2017 \| Customer relationships
Acquisitions
Identifiable intangible assets \| $	$ 43.0
Weighted average amortizable lives of identifiable intangible assets	6 years 4 months 15 days
Acquisitions, 2016 \| Land segment
Acquisitions
Number of businesses acquired \| acquisition		3

Number of airports to be acquired through a definitive agreement.

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Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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- Definition

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- References

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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

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- Definition

The number of businesses acquired by the entity during the period.

+ References

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