XML 15 R25.htm IDEA: XBRL DOCUMENT v2.4.1.9

Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 segment	Mar. 31, 2014
Segment Reporting Information [Line Items]
Number of operating segments	1us-gaap_NumberOfOperatingSegments
Revenue	$ 24,741us-gaap_SalesRevenueNet	$ 22,322us-gaap_SalesRevenueNet
Operating costs and expenses	18,954us-gaap_CostsAndExpenses	17,960us-gaap_CostsAndExpenses
Other income, net	39us-gaap_NonoperatingIncomeExpense	3us-gaap_NonoperatingIncomeExpense
Income before provision for income taxes	5,826us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	4,365us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Rental
Segment Reporting Information [Line Items]
Revenue	20,603us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember	18,789us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember
Operating costs and expenses	7,727us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember	7,956us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember
Other income, net	0us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember	0us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember
Income before provision for income taxes	12,876us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember	10,833us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentRentalMember
Sales
Segment Reporting Information [Line Items]
Revenue	3,912us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember	3,338us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember
Operating costs and expenses	2,813us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember	2,235us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember
Other income, net	0us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember	0us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember
Income before provision for income taxes	1,099us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember	1,103us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentSalesMember
Service & Maintenance
Segment Reporting Information [Line Items]
Revenue	226us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember	195us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember
Operating costs and expenses	38us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember	84us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember
Other income, net	0us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember	0us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember
Income before provision for income taxes	188us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember	111us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = ngs_OperatingSegmentServiceAndMaintenanceMember
Corporate
Segment Reporting Information [Line Items]
Revenue	0us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember	0us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember
Operating costs and expenses	8,376us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember	7,685us-gaap_CostsAndExpenses / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember
Other income, net	39us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember	3us-gaap_NonoperatingIncomeExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember
Income before provision for income taxes	$ (8,337)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember	$ (7,682)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateMember

X

- Definition

Total costs of sales and operating expenses for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	debit
Period Type:	duration

X

- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=51673353&loc=d3e41242-110953



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

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X

- Definition

The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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X

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

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Balance Type:	na
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X

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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X

- Details

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X

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