Asset Disposals and Impairments - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Assets Held For Sale And Impairments [Line Items]
Carrying value of aircraft	$ 876,317,000		$ 876,317,000		$ 785,472,000
Gain on disposal of assets	(56,000)	1,399,000	(1,371,000)	16,075,000
Light Aircraft [Member] | Oil and Gas [Member]
Assets Held For Sale And Impairments [Line Items]
Carrying value of aircraft		1,200,000		1,200,000
Sale value of aircraft	0	2,600,000
Gain on disposal of assets		$ 1,400,000
Number of aircraft sold		1