XML 51 R39.htm IDEA: XBRL DOCUMENT v3.20.2

Rental Equipment (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) compressor	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Retirement of rental equipment	$ 0	$ 1,512,000	$ 0	$ 1,512,000
Compressor units
Property, Plant and Equipment [Line Items]
Number of units retired | compressor		327
Compressor units | Loss On Retirement of Rental Equipment
Property, Plant and Equipment [Line Items]
Retirement of rental equipment			$ 0	$ 1,500,000

X

- Definition

Number Of Units Retired

+ References

No definition available.

+ Details

Name:	ngs_NumberOfUnitsRetired
Namespace Prefix:	ngs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Loss recognized as a result of the initial and subsequent write-down of a long-lived asset's carrying amount to fair value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

+ Details

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

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleByTypeAxis=ngs_RentalCompressorUnitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=ngs_LossOnRetirementOfRentalEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: