Condensed Consolidating Financial Information - Summary of Condensed Consolidating Financial Position (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 107,855		$ 87,022
Accounts receivable
Trade, net	67,042		107,842
Joint interest, net	52,777		16,552
Other	21,697		6,346
Assets from price risk management activities	72,666		8,393
Prepaid assets	45,689		65,877
Other current assets	1,982		1,952
Total current assets	369,708		293,984
Property and equipment:
Proved properties	4,674,529		4,066,260
Unproved properties, not subject to amortization	274,690		194,532
Other property and equipment	32,262		29,843
Total property and equipment	4,981,481		4,290,635
Accumulated depreciation, depletion and amortization	(2,247,009)		(2,065,023)
Total property and equipment, net	2,734,472		2,225,612
Other long-term assets:
Assets from price risk management activities	1,409
Other well equipment inventory	14,458		7,732
Operating lease assets	7,351		7,779
Other assets	47,250		54,375
Total assets	3,174,648		2,589,482
Current liabilities:
Accounts payable	104,151		71,357
Accrued liabilities	184,992		154,816
Accrued royalties	12,772		31,729
Current portion of asset retirement obligations	44,977		61,051
Liabilities from price risk management activities	26,615		19,476
Accrued interest payable	10,603		10,249
Current portion of operating lease liabilities	1,695		1,594
Other current liabilities	22,073		20,180
Total current liabilities	407,878		370,452
Long-term liabilities:
Long-term debt, net of discount and deferred financing costs	997,041		732,981
Asset retirement obligations	387,083		308,427
Liabilities from price risk management activities	7,018		511
Operating lease liabilities	19,228		17,239
Other long-term liabilities	61,847		81,595
Total liabilities	1,880,095		1,511,205
Commitments and Contingencies
Stockholders' equity	1,294,553	$ 1,394,897	1,078,277	$ 998,041	$ 899,986	$ 1,007,496
Total liabilities and stockholders' equity	3,174,648		2,589,482
Parent
Accounts receivable
Prepaid assets	166
Other current assets	53
Total current assets	219
Other long-term assets:
Investments in subsidiaries	1,267,766		1,045,886
Other assets	27,756		33,371
Total assets	1,295,741		1,079,257
Current liabilities:
Accounts payable	636		428
Other current liabilities	255		255
Total current liabilities	891		683
Long-term liabilities:
Other long-term liabilities	297		297
Total liabilities	1,188		980
Commitments and Contingencies
Stockholders' equity	1,294,553		1,078,277
Total liabilities and stockholders' equity	1,295,741		1,079,257
Subsidiary Issuer
Current assets:
Cash and cash equivalents	102,310		78,780
Accounts receivable
Other	16,044		474
Assets from price risk management activities	72,666		8,393
Prepaid assets	8,748		33,323
Total current assets	199,768		120,970
Property and equipment:
Other property and equipment	25,119		23,142
Total property and equipment	25,119		23,142
Accumulated depreciation, depletion and amortization	(12,523)		(11,001)
Total property and equipment, net	12,596		12,141
Other long-term assets:
Assets from price risk management activities	1,409
Operating lease assets	3,400		3,178
Investments in subsidiaries	2,111,292		1,690,362
Other assets	364		364
Total assets	2,328,829		1,827,015
Current liabilities:
Accounts payable	4,108		5,145
Accrued liabilities	4,851		4,740
Liabilities from price risk management activities	26,615		19,476
Accrued interest payable	10,565		10,211
Current portion of operating lease liabilities	560		196
Total current liabilities	46,699		39,768
Long-term liabilities:
Long-term debt, net of discount and deferred financing costs	990,981		726,921
Liabilities from price risk management activities	7,018		511
Operating lease liabilities	16,365		13,929
Total liabilities	1,061,063		781,129
Commitments and Contingencies
Stockholders' equity	1,267,766		1,045,886
Total liabilities and stockholders' equity	2,328,829		1,827,015
Guarantors
Current assets:
Cash and cash equivalents	1,791		593
Accounts receivable
Trade, net	67,042		107,842
Joint interest, net	39,793		11,567
Other	5,394		5,555
Prepaid assets	36,747		32,529
Other current assets	1,929		1,952
Total current assets	152,696		160,038
Property and equipment:
Proved properties	4,674,529		4,066,260
Unproved properties, not subject to amortization	159,063		87,618
Other property and equipment	6,926		6,484
Total property and equipment	4,840,518		4,160,362
Accumulated depreciation, depletion and amortization	(2,234,408)		(2,053,971)
Total property and equipment, net	2,606,110		2,106,391
Other long-term assets:
Other well equipment inventory	14,458		7,732
Operating lease assets	2,830		3,224
Other assets	2,408		2,136
Total assets	2,778,502		2,279,521
Current liabilities:
Accounts payable	98,638		58,827
Accrued liabilities	168,996		145,051
Accrued royalties	12,772		31,729
Current portion of asset retirement obligations	44,977		61,051
Accrued interest payable	38		38
Current portion of operating lease liabilities	723		821
Other current liabilities	21,818		19,925
Total current liabilities	347,962		317,442
Long-term liabilities:
Long-term debt, net of discount and deferred financing costs	6,060		6,060
Asset retirement obligations	387,083		308,427
Operating lease liabilities	2,115		2,416
Other long-term liabilities	61,550		81,298
Total liabilities	804,770		715,643
Commitments and Contingencies
Stockholders' equity	1,973,732		1,563,878
Total liabilities and stockholders' equity	2,778,502		2,279,521
Non-Guarantors
Current assets:
Cash and cash equivalents	3,754		7,649
Accounts receivable
Joint interest, net	12,984		4,985
Other	259		317
Prepaid assets	28		25
Total current assets	17,025		12,976
Property and equipment:
Unproved properties, not subject to amortization	115,627		106,914
Other property and equipment	217		217
Total property and equipment	115,844		107,131
Accumulated depreciation, depletion and amortization	(78)		(51)
Total property and equipment, net	115,766		107,080
Other long-term assets:
Operating lease assets	1,121		1,377
Other assets	16,722		18,504
Total assets	150,634		139,937
Current liabilities:
Accounts payable	769		6,957
Accrued liabilities	11,145		5,025
Current portion of operating lease liabilities	412		577
Total current liabilities	12,326		12,559
Long-term liabilities:
Operating lease liabilities	748		894
Total liabilities	13,074		13,453
Commitments and Contingencies
Stockholders' equity	137,560		126,484
Total liabilities and stockholders' equity	150,634		139,937
Elimination
Other long-term assets:
Investments in subsidiaries	(3,379,058)		(2,736,248)
Total assets	(3,379,058)		(2,736,248)
Long-term liabilities:
Commitments and Contingencies
Stockholders' equity	(3,379,058)		(2,736,248)
Total liabilities and stockholders' equity	$ (3,379,058)		$ (2,736,248)