Asset Disposals and Impairments - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Assets Held For Sale And Impairments [Line Items]
Gain (loss) on sale of aircraft	$ (1,073,000)	$ (25,000)
Light Aircraft [Member] \| Oil And Gas [Member]
Assets Held For Sale And Impairments [Line Items]
Sale value of aircraft	3,000,000
Gain (loss) on sale of aircraft	$ (1,100,000)
Number of aircraft sold	2
Fixed Wing Aircraft [Member] \| Oil And Gas [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold	2

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2941-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Name:	us-gaap_GainLossOnDispositionOfAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration