Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

Name:	us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Commitments and Contingencies - Additional Information (Details) $ in Millions		12 Months Ended
	Nov. 02, 2014 Stockholder	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	May 31, 2016 Well
Commitments And Contingencies Disclosure [Abstract]
Number of purported stockholders \| Stockholder	2
Number of exploration wells \| Well					2
Office and delay rental expense \| $		$ 9.2	$ 12.4	$ 12.8