XML 68 R53.htm IDEA: XBRL DOCUMENT
v3.21.1

Credit Facility (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 USD ($) loan | Dec. 31, 2019 USD ($)
Line of Credit Facility [Line Items] |  |
Line of credit | $ 417,000 | $ 417,000
Weighted average interest rate | 2.75% |
Revolving Credit Facility |  |
Line of Credit Facility [Line Items] |  |
Aggregate credit agreement commitment | $ 30,000,000 |
Potential increase in borrowing capacity | 20,000,000 |
Potential maximum borrowing capacity | $ 50,000,000 |
Borrowing base, component, % of eligible accounts receivable | 80.00% |
Borrowing base, component, % of eligible inventory | 50.00% |
Borrowing base, allowable share of total commitment amount attributable to inventory component | 50.00% |
Borrowing base, component, % of eligible equipment inventory | 75.00% |
Borrowing base amount available | $ 29,500,000 |
Line of credit | $ 417,000 |
Revolving Credit Facility | Minimum |  |
Line of Credit Facility [Line Items] |  |
Minimum commitment coverage ratio allowed | 2.00 |
Revolving Credit Facility | Maximum |  |
Line of Credit Facility [Line Items] |  |
Maximum leverage ratio allowed | 2.50 |
Default trigger, certain defaults of other company indebtedness, amount | $ 50,000 |
Default trigger, rendering of certain judgments, amount | $ 150,000 |
Revolving Credit Facility | LIBOR Rate |  |
Line of Credit Facility [Line Items] |  |
Variable rate, applicable margin | 1.50% |
Revolving Credit Facility | LIBOR Rate | Maximum |  |
Line of Credit Facility [Line Items] |  |
Reference rate, number of allowable LIBOR-based borrowings outstanding (in loans) | loan | 3 |
Revolving Credit Facility | CB Floating Rate |  |
Line of Credit Facility [Line Items] |  |
Variable rate, applicable margin | 1.25% |

X
- Definition Line of Credit Facility, Minimum Commitment Coverage Ratio Allowed + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityCommitmentCoverageRatio
Namespace Prefix: | ngs_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line Of Credit Facility, Current Borrowing Capacity, Allowable Share Of Total Commitment Amount Attributable To General Inventory Component + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityCurrentBorrowingCapacityAllowableShareOfTotalCommitmentAmountAttributableToGeneralInventoryComponent
Namespace Prefix: | ngs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line Of Credit Facility, Current Borrowing Capacity, Component, Percentage Of Eligible Accounts Receivable + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleAccountsReceivable
Namespace Prefix: | ngs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line Of Credit Facility, Current Borrowing Capacity, Component, Percentage Of Eligible Equipment Inventory + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleEquipmentInventory
Namespace Prefix: | ngs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line Of Credit Facility, Current Borrowing Capacity, Component, Percentage Of Eligible General Inventory + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleGeneralInventory
Namespace Prefix: | ngs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line Of Credit Facility, Default Trigger, Certain Defaults Of Other Company Indebtedness, Amount + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityDefaultTriggerCertainDefaultsOfOtherCompanyIndebtednessAmount
Namespace Prefix: | ngs_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line Of Credit Facility, Default Trigger, Rendering Of Certain Judgments, Amount + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityDefaultTriggerRenderingOfCertainJudgmentsAmount
Namespace Prefix: | ngs_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line of Credit Facility, Maximum Leverage Ratio Allowed + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityLeverageRatio
Namespace Prefix: | ngs_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line Of Credit Facility, Potential Increase In Borrowing Capacity + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityPotentialIncreaseInBorrowingCapacity
Namespace Prefix: | ngs_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line Of Credit Facility, Potential Maximum Borrowing Capacity + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityPotentialMaximumBorrowingCapacity
Namespace Prefix: | ngs_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line Of Credit Facility, Reference Rate, Number Of Allowable Borrowings Outstanding + References No definition available. + Details
Name: | ngs_LineOfCreditFacilityReferenceRateNumberOfAllowableBorrowingsOutstanding
Namespace Prefix: | ngs_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The effective interest rate during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
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_LineOfCreditFacilityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LinesOfCreditCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=ngs_CbFloatingRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |