Risk Management Activities (Details)		3 Months Ended
		Mar. 31, 2019 USD ($) MMBTU $ / bbl $ / MMBTU bbl	Dec. 31, 2018 USD ($)
Derivatives, Fair Value [Line Items]
Assets from Price Risk Management Activities		$ 3,909,000	$ 23,806,000
Liabilities from Price Risk Management Activities		746,000	0
Derivative Collateral [Abstract]
Collateral Had on Derivative		0	0
Collateral Held on Derivative		0	0
Liabilities From Price Risk Management Activities
Derivatives, Fair Value [Line Items]
Assets from Price Risk Management Activities		1,000,000
Liabilities from Price Risk Management Activities		2,000,000
Liabilities From Price Risk Management Activities | Price Risk Derivative [Member]
Derivatives, Fair Value [Line Items]
Liabilities from Price Risk Management Activities	[1]	746,000	0
Assets From Price Risk Management Activities
Derivatives, Fair Value [Line Items]
Assets from Price Risk Management Activities		7,000,000
Liabilities from Price Risk Management Activities		3,000,000
Assets From Price Risk Management Activities | Price Risk Derivative [Member]
Derivatives, Fair Value [Line Items]
Assets from Price Risk Management Activities	[2]	$ 3,909,000	$ 23,806,000
Crude Oil | Midland Differential Basis Swaps | Derivative Contracts - January through April (closed) [Member]
Derivatives, Fair Value [Line Items]
Volume (Bbld) | bbl		20,000
Derivative, Swap Type, Average Fixed Price | $ / bbl		1.075
Crude Oil | Midland Differential Basis Swaps | Derivative Contracts - May through December [Member]
Derivatives, Fair Value [Line Items]
Volume (Bbld) | bbl		20,000
Derivative, Swap Type, Average Fixed Price | $ / bbl		1.075
Crude Oil | Gulf Coast Differential Basis Swap | Derivative Contracts - January through April (closed) [Member]
Derivatives, Fair Value [Line Items]
Volume (Bbld) | bbl		13,000
Derivative, Swap Type, Average Fixed Price | $ / bbl		5.572
Crude Oil | Gulf Coast Differential Basis Swap | Derivative Contracts - May through December [Member]
Derivatives, Fair Value [Line Items]
Volume (Bbld) | bbl		13,000
Derivative, Swap Type, Average Fixed Price | $ / bbl		5.572
Crude Oil | Price Swaps | Derivative Contracts - January through September (closed) [Member]
Derivatives, Fair Value [Line Items]
Volume (Bbld) | bbl		25,000
Derivative, Swap Type, Average Fixed Price | $ / bbl		60.00
Natural Gas | Price Swaps | Derivative Contracts - April (closed) [Member]
Derivatives, Fair Value [Line Items]
Derivative, Swap Type, Average Fixed Price | $ / MMBTU		2.90
Volume (MMBtud) | MMBTU		250,000
Natural Gas | Price Swaps | Derivative Contracts - May through October [Member]
Derivatives, Fair Value [Line Items]
Derivative, Swap Type, Average Fixed Price | $ / MMBTU		2.90
Volume (MMBtud) | MMBTU		250,000

[1] The current portion of Liabilities from Price Risk Management Activities consists of gross liabilities of $2 million, partially offset by gross assets of $1 million at March 31, 2019.

[2] The current portion of Assets from Price Risk Management Activities consists of gross assets of $7 million, partially offset by gross liabilities of $3 million at March 31, 2019.