Derivative Contracts Schedule Of Commodity Derivative Contracts (Details) MMBTU in Millions	6 Months Ended
	Jun. 30, 2017 USD ($) MMBTU $ / MMBTU
Oil Basis Swaps [Member] | Production [Member] | Year 2017 [Member] | NYMEX WTI less Argus WTI Midland [Member]
Derivative [Line Items]
Derivative Volumes	2.2
Weighted-Average Differential | $ / MMBTU	(0.67)
Oil Basis Swaps [Member] | Production [Member] | Year 2018 [Member] | NYMEX WTI less Argus WTI Midland [Member]
Derivative [Line Items]
Derivative Volumes	6.2
Weighted-Average Differential | $ / MMBTU	(1.09)
Oil Basis Swaps [Member] | Production [Member] | Year 2019 [Member] | NYMEX WTI less Argus WTI Midland [Member]
Derivative [Line Items]
Derivative Volumes	0.4
Weighted-Average Differential | $ / MMBTU	(1.10)
Gas Swaps [Member] | Production [Member] | Year 2017 [Member] | NYMEX HH [Member]
Derivative [Line Items]
Derivative Volumes	49.7
Average Swap Price per Unit | $	$ 2.87
Gas Swaps [Member] | Production [Member] | Year 2017 [Member] | IFNPCR [Member]
Derivative [Line Items]
Derivative Volumes	16.6
Average Swap Price per Unit | $	$ 2.51
Gas Swaps [Member] | Production [Member] | Year 2018 [Member] | NYMEX HH [Member]
Derivative [Line Items]
Derivative Volumes	98.6
Average Swap Price per Unit | $	$ 2.99
Gas Swaps [Member] | Production [Member] | Year 2019 [Member] | NYMEX HH [Member]
Derivative [Line Items]
Derivative Volumes	3.7
Average Swap Price per Unit | $	$ 2.85
Gas Swaps [Member] | Storage [Member] | Year 2017 [Member] | IFNPCR [Member]
Derivative [Line Items]
Derivative Volumes	1.1
Average Swap Price per Unit | $	$ 2.83
Oil Swaps [Member] | Production [Member] | Year 2017 [Member] | NYMEX WTI [Member]
Derivative [Line Items]
Derivative Volumes	7.2
Average Swap Price per Unit | $	$ 51.51
Oil Swaps [Member] | Production [Member] | Year 2018 [Member] | NYMEX WTI [Member]
Derivative [Line Items]
Derivative Volumes	9.9
Average Swap Price per Unit | $	$ 53.59
Gas Collars [Member] | Production [Member] | Year 2017 [Member] | NYMEX HH [Member]
Derivative [Line Items]
Derivative Volumes	5.5
Derivative Average Price Floor | $	$ 2.50
Derivative Average Price Ceiling | $	$ 3.50
Gas Basis Swaps [Member] | Production [Member] | Year 2017 [Member] | NYMEX HH LESS IFNPCR [Member]
Derivative [Line Items]
Derivative Volumes	25.8
Weighted-Average Differential | $ / MMBTU	(0.18)
Gas Basis Swaps [Member] | Production [Member] | Year 2018 [Member] | NYMEX HH LESS IFNPCR [Member]
Derivative [Line Items]
Derivative Volumes	7.3
Weighted-Average Differential | $ / MMBTU	(0.16)