Other Accrued Expenses Other Accrued Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Schedule of Other Liabilities [Line Items]
Amortization of Other Deferred Charges	$ 500
Production Tax Liability	140,175	$ 68,020
Deferred Midstream gathering credits	174,638	175,897
Operating and Finance Lease Liability, Noncurrent	16,083	15,779
Other Accrued Liabilities, Noncurrent	$ 353,378	283,133
Document Period End Date	Mar. 31, 2020
Non Current Liabilities
Schedule of Other Liabilities [Line Items]
Increase (Decrease) in Accrued Cost of Oil and Gas Reclamation	$ 19,597	20,100
Other Accrued Liabilities	2,885	3,337
Current Liabilities
Schedule of Other Liabilities [Line Items]
Other Accrued Liabilities	12,681	$ 8,469
Midstream Oil Gathering [Member]
Schedule of Other Liabilities [Line Items]
Amortization of Other Deferred Charges	200
MIdstream Water Gathering [Member]
Schedule of Other Liabilities [Line Items]
Amortization of Other Deferred Charges	300
Midstream Gas Gathering [Member]
Schedule of Other Liabilities [Line Items]
Amortization of Other Deferred Charges	$ 800