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Fair Value Measurements - Additional Information (Details)	6 Months Ended
	Jun. 30, 2019 USD ($) engine	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Fair Value Disclosures [Abstract]
Fair value of notes receivable	$ 30,900,000		$ 200,000
Fair value of notes payable	1,265,000,000.0		1,348,100,000
Derivative [Line Items]
Increase in interest expense	(400,000)	$ (100,000)
Increase (decrease) in asset write-down	$ 4,400,000	$ 3,600,000
Number of engines | engine	4
Number of assets impaired | engine	3
Interest rate contract
Derivative [Line Items]
Notional amount outstanding	$ 100,000,000.0		100,000,000
Notional amount, liability	$ 22,000
Assets at fair value			$ 1,700,000

X

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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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- Definition

Fair value portion of notes payable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20,22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Fair value portion of an agreement for an unconditional promise by the maker to pay the holder a definite sum of money at a future date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Fair value portion of liabilities pertaining to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Examples include, but are not limited to, short positions in securities, derivatives and commodities.

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Increase (Decrease) in Asset Impairment Charges

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Increase (Decrease) In Interest Expense

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Number Of Assets Impaired

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Number of Engines

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