Summary of Significant Accounting Policies - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	$ (106)	$ (203)
Total accounts receivable	72,943	51,415
Accrued oil, gas and NGL sales [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable gross	44,860	36,569
Due from joint interest owners [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable gross	27,435	14,779
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable gross	$ 754	$ 270