Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

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

COMMITMENTS AND CONTINGENCIES (Detail) $ in Thousands	1 Months Ended
COMMITMENTS AND CONTINGENCIES (Detail) $ in Thousands	Feb. 29, 2016 well	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)
Loss Contingencies [Line Items]
Number of wells, gas migration detected \| well	1
Percentage of working interest		50.00%
Accrual for environmental remediation costs		$ 200	$ 200
Minimum [Member]
Loss Contingencies [Line Items]
Estimate of probable loss		400
Maximum [Member]
Loss Contingencies [Line Items]
Estimate of probable loss		$ 800