Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 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):

	June 30, 2018			December 31, 2017
Oil and natural gas properties:
Unproved	$	547,963		$	459,549
Proved		2,027,472			1,896,081
Gross oil and natural gas properties		2,575,435			2,355,630
Less accumulated depreciation, depletion and amortization		(1,311,180	)		(1,248,200	)
Oil and natural gas properties, net		1,264,255			1,107,430
Other property and equipment		14,450			13,508
Less accumulated depreciation		(7,501	)		(6,566	)
Other property and equipment, net		6,949			6,942
Property and equipment, net	$	1,271,204		$	1,114,372

Summary of Revenue Disaggregated by Type

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

	Three Months Ended June 30,					Six Months Ended June 30,
	2018		2017			2018		2017
Revenues (in thousands)
Natural gas sales	$	54,409	$	59,890		$	112,892	$	121,310
NGL sales		18,702		11,151			38,446		28,213
Oil sales		30,146		15,153			62,103		36,102
Brokered natural gas and marketing revenue		365		(3	)		373		2,428
Total revenues	$	103,622	$	86,191		$	213,814	$	188,053

Changes in Company's Asset Retirement Obligation Liability

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

	Six Months Ended June 30, 2018
Asset retirement obligations, beginning of period	$	6,029
Additional liabilities incurred		208
Accretion		317
Asset retirement obligations, end of period	$	6,554

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

Concentration Risk

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

	June 30, 2018		December 31, 2017
Receivables by product or service:
Sale of oil and natural gas and related products    and services	$	51,959	$	52,908
Joint interest owners		59,512		23,154
Derivatives		665		1,528
Other		30		19
Total	$	112,166	$	77,609