Additional Balance Sheet Information - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts receivable, net
Trade accounts	$ 362,973	$ 215,511
Joint interest accounts	101	467
Other accounts	567	1,312
Receivables gross current	363,641	217,290
Allowance for doubtful accounts	(1,238)	(1,286)
Accounts receivable, net	362,403	216,004
Other assets
Deferred compensation plan	14,699	14,966
Debt issuance cost	4,572	7,990
Income taxes receivable	8,165	0
Other accounts	61	56
Other assets	27,497	23,012
Accounts payable
Trade accounts	30,033	7,815
Natural gas purchases	0	4,299
Royalty and other owners	61,507	39,207
Accrued transportation	50,540	51,433
Accrued capital costs	43,207	31,130
Taxes other than income	19,824	16,801
Income taxes payable	1,134	0
Deposits received for asset sales	0	81,500
Other accounts	35,694	5,860
Accounts payable current	241,939	238,045
Accrued liabilities
Employee benefits	21,761	20,645
Taxes other than income	1,472	550
Asset retirement obligations	1,000	4,952
Other accounts	994	1,294
Accrued liabilities	25,227	27,441
Other liabilities
Deferred compensation plan	25,780	29,145
Other accounts	34,391	10,578
Other liabilities	$ 60,171	$ 39,723