Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 61,157	$ 35,532
Trade accounts receivable, net of allowance for doubtful accounts of $616 and $833, respectively	5,332	9,107
Inventory, net	24,368	27,722
Prepaid income taxes	979	81
Prepaid expenses and other	519	762
Total current assets	92,355	73,204
Rental equipment, net of accumulated depreciation of $126,104 and $111,293, respectively	179,561	191,933
Property and equipment, net of accumulated depreciation of $11,534 and $10,825 respectively	7,817	8,527
Goodwill	10,039	10,039
Intangibles, net of accumulated amortization of $1,476 and $1,382, respectively	1,683	1,777
Other assets	169	73
Total assets	291,624	285,553
Current Liabilities:
Accounts payable	902	1,226
Accrued liabilities	2,845	3,071
Deferred income	1,900	271
Total current liabilities	5,647	4,568
Line of credit, non-current portion	417	417
Deferred income tax liability	54,685	56,458
Other long-term liabilities	271	129
Total liabilities	61,020	61,572
Commitments and contingencies
Stockholders’ Equity:
Preferred stock, 5,000 shares authorized, no shares issued or outstanding	0	0
Common stock, 30,000 shares authorized, par value $0.01; 12,724 and 12,603 shares issued and outstanding, respectively	127	126
Additional paid-in capital	99,623	98,310
Retained earnings	130,854	125,545
Total stockholders' equity	230,604	223,981
Total liabilities and stockholders' equity	$ 291,624	$ 285,553

Rental Equipment, Net

No definition available.

Name:	ngs_RentalEquipmentNet
Namespace Prefix:	ngs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).