Asset Disposals - Additional Information (Detail) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($) Aircraft
Assets Held For Sale And Impairments [Line Items]
Cash realized from sale of assets \| $	$ 0.0	$ 0.8
Gain (loss) on disposal of assets \| $		$ (0.9)
Air Medical [Member] \| Light Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold \| Aircraft		1
Oil and Gas [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft donated \| Aircraft		1

Assets Held For Sale And Impairments [Line Items]

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- Definition

Property, Plant and Equipment, Number of Aircraft Donated

+ References

No definition available.

+ Details

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- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

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- Definition

The cash inflow from the sale of property, plant and equipment (capital expenditures), software, and other intangible assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

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- Definition

The number of aircraft sold by the entity during the period.

+ References

No definition available.

+ Details

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