Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Summary of Property and Equipment Including Oil and Natural Gas Properties

A summary of property and equipment including oil and natural gas properties is as follows (in thousands):

	September 30, 2018			December 31, 2017
Oil and natural gas properties:
Unproved	$	485,123		$	459,549
Proved		2,147,024			1,896,081
Gross oil and natural gas properties		2,632,147			2,355,630
Less accumulated depreciation, depletion and amortization		(1,344,998	)		(1,248,200	)
Oil and natural gas properties, net		1,287,149			1,107,430
Other property and equipment		14,344			13,508
Less accumulated depreciation		(7,726	)		(6,566	)
Other property and equipment, net		6,618			6,942
Property and equipment, net	$	1,293,767		$	1,114,372

Summary of Revenue Disaggregated by Type

The following table illustrates the revenue disaggregated by type for the three and nine months ended September 30, 2018 and 2017:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Revenues (in thousands)
Natural gas sales	$	65,756	$	65,970	$	178,648	$	187,280
NGL sales		25,074		13,741		63,520		41,954
Oil sales		36,349		11,838		98,452		47,940
Brokered natural gas and marketing revenue		2,944		—		3,318		2,428
Total revenues	$	130,123	$	91,549	$	343,938	$	279,602

Changes in Company's Asset Retirement Obligation Liability

The following table sets forth the changes in the Company’s ARO liability for the nine months ended September 30, 2018 (in thousands):

	Nine Months Ended September 30, 2018
Asset retirement obligations, beginning of period	$	6,029
Additional liabilities incurred		388
Accretion		486
Asset retirement obligations, end of period	$	6,903

Accounts Receivable [Member] | Product Concentration Risk [Member]

Concentration Risk

The following table summarizes the Company’s concentration of receivables, net of allowances (if any), by product or service as of September 30, 2018 and December 31, 2017 (in thousands):

	September 30, 2018		December 31, 2017
Receivables by product or service:
Sale of oil and natural gas and related products    and services	$	75,205	$	52,908
Joint interest owners		49,450		23,154
Derivatives		602		1,528
Other		28		19
Total	$	125,285	$	77,609