Transactions with Affiliates (Details) - USD ($)		1 Months Ended	3 Months Ended
	Jul. 15, 2019	Jun. 30, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Net amount direct billed and allocated (to)/from affiliates			$ 25,676,000	$ 29,476,000
Current accounts receivable - affiliates			2,937,000		$ 2,032,000
Current accounts payable - affiliates			934,000		1,009,000
Revenues recorded in net asset optimization revenues related to affiliates			321,000	2,552,000
Cash received for disgorgement of stockholders short-swing profits			0	46,000
Affiliated Entity | Subordinated Debt Facility
Related Party Transaction [Line Items]
Subordinated debt—affiliate		$ 25,000,000.0
Subordinated debt, advances		$ 1,000,000.0
Subordinated debt, interest rate on advances		5.00%
Outstanding under subordinated note					$ 0
Affiliated Entity | Allocated Overhead Costs
Related Party Transaction [Line Items]
Net amount direct billed and allocated (to)/from affiliates			200,000	100,000
Affiliated Entity | Purchased Natural Gas From Affiliate
Related Party Transaction [Line Items]
Cost of revenues recorded in net asset optimization revenues (less than)			200,000	100,000
NuDevco Retail Holdings and NuDevco Retail
Related Party Transaction [Line Items]
Distributions to affiliates			3,800,000	3,800,000
NuDevco Retail Holdings and NuDevco Retail | Payment of Income Taxes Incurred by the Company
Related Party Transaction [Line Items]
Distributions to affiliates			3,400,000	0
Retailco and NuDevco Retail
Related Party Transaction [Line Items]
Cash payment to acquire business	$ 11,200,000
Affiliated Entity
Related Party Transaction [Line Items]
Revenues recorded in net asset optimization revenues related to affiliates			$ 500,000	$ 1,200,000
Spark HoldCo
Related Party Transaction [Line Items]
Distributions to affiliates	$ 16,300,000