Amount of letters of credit and other surety bonds that are available for the future payment of malpractice claims.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 450
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6491354&loc=d3e6049-115624

Name:	us-gaap_MalpracticeLossContingencyLettersOfCreditAndSuretyBonds
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Commitments and Contingencies - Additional Information (Detail) - Bureau of Ocean Energy Management - USD ($) $ in Millions	Dec. 31, 2016	Jun. 30, 2016	Mar. 21, 2016
Loss Contingencies [Line Items]
Bonding requirement, amount			$ 565
Surety bond		$ 230
Scenario, Forecast
Loss Contingencies [Line Items]
Bonding requirement, amount	$ 16