Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) Customer Institution Segment	Dec. 31, 2017 USD ($) Customer	Dec. 31, 2016 USD ($) Customer	Jan. 01, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | Segment	1
Cumulative effect of adoption of ASU 2018-02 reclassified to retained earnings	$ 446,000
Unsatisfied performance obligations	$ 10,100,000,000
Number of financial institutions | Institution	1
Amortization of unproved properties included in depreciation, depletion, and amortization	$ 82,300,000	$ 52,800,000	$ 25,000,000
Assets legally restricted for purposes of settling asset retirement obligations	0
Receivables from contracts with customers	363,000,000	215,500,000
Concentration Risk [Line Items]
Cumulative effect of adoption of ASU 2018-02 reclassified to retained earnings	$ 446,000	$ 0	$ 0
Minimum
Properties and Equipment
Unsatisfied performance obligations, expected period of satisfaction	5 years
Maximum
Properties and Equipment
Unsatisfied performance obligations, expected period of satisfaction	20 years
Gathering and pipeline systems and equipment | Minimum
Properties and Equipment
Estimated useful life	10 years
Gathering and pipeline systems and equipment | Maximum
Properties and Equipment
Estimated useful life	25 years
Buildings | Minimum
Properties and Equipment
Estimated useful life	25 years
Buildings | Maximum
Properties and Equipment
Estimated useful life	40 years
Other assets | Minimum
Properties and Equipment
Estimated useful life	3 years
Other assets | Maximum
Properties and Equipment
Estimated useful life	10 years
Sales Revenue, Net | Customer
Concentration Risk [Line Items]
Number of customers | Customer	3	2	2
Forecast | Minimum | ASU 2016-02
Properties and Equipment
Operating lease liability				$ 40,000,000
Operating lease, right of use asset				40,000,000
Forecast | Maximum | ASU 2016-02
Properties and Equipment
Operating lease liability				60,000,000
Operating lease, right of use asset				$ 60,000,000
Customer one | Sales Revenue, Net | Customer
Concentration Risk [Line Items]
Percentage of total sales	20.00%	18.00%	19.00%
Customer two | Sales Revenue, Net | Customer
Concentration Risk [Line Items]
Percentage of total sales	11.00%	11.00%	10.00%
Customer three | Sales Revenue, Net | Customer
Concentration Risk [Line Items]
Percentage of total sales	9.00%