Joint Interest Billings (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Joint interest billings
Long-term receivables - joint interest billings	$ 45,663	$ 37,687
TEN Discoveries \| GNPC
Joint interest billings
Long-term receivables - joint interest billings	$ 44,000	$ 35,300
TEN Discoveries \| GNPC
Joint interest billings
GNPC's paying interest (as a percent)	5.00%

Noncurrent portion of accounts receivable attributable to joint interest partners in oil and gas properties. These are billings to the non-operators associated with the operation of wells and are based on those owners' working interests in the wells.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 323
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6474814&loc=d3e64006-109457

Name:	us-gaap_OilAndGasJointInterestBillingReceivablesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant