Asset Held for Sale - Additional Information (Detail) - USD ($)	3 Months Ended
Jun. 30, 2017	Mar. 31, 2017
Asset Held For Sale Current [Abstract]
Net book value of airport facility reclassified as an assets held for sale, current	$ 1,529,000	$ 1,500,000
Changes to assets held for sale	$ 0

The increase (decrease) during the period in book value of long-lived assets that the reporting entity plans to sell within one year (or one business cycle).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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