Asset Disposals - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2016 USD ($) Aircraft	Sep. 30, 2015 USD ($) Aircraft	Jun. 30, 2016 USD ($) Aircraft
Assets Held For Sale And Impairments [Line Items]
Cash realized from sale of assets | $	$ 2.2	$ 2.3	$ 11.0
Gain (loss) on disposal of assets | $	$ (0.1)	$ 0.2	$ 3.9
Oil and Gas [Member] | Light Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold | Aircraft	4	6	5
Oil and Gas [Member] | Medium Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold | Aircraft			3