Derivative And Financial Instruments (Hedges In Place) (Details)	6 Months Ended
	Jun. 30, 2017 MMBTU $ / bbl $ / MMBTU bbl
West Texas Intermediate 2017 Swap Quarter 3 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	87,304
Average Price | $ / bbl	61.42
West Texas Intermediate 2017 Swap Quarter 4 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	81,702
Average Price | $ / bbl	61.55
West Texas Intermediate 2017 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	169,006
Average Price | $ / bbl	61.48
West Texas Intermediate 2018 Swap Quarter 1 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	88,854
Average Price | $ / bbl	60.82
West Texas Intermediate 2018 Swap Quarter 2 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	83,976
Average Price | $ / bbl	60.90
West Texas Intermediate 2018 Swap Quarter 3 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	79,683
Average Price | $ / bbl	60.96
West Texas Intermediate 2018 Swap Quarter 4 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	75,864
Average Price | $ / bbl	61.02
West Texas Intermediate 2018 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	328,377
Average Price | $ / bbl	60.92
West Texas Intermediate 2019 Swap Quarter 1 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	78,667
Average Price | $ / bbl	61.48
West Texas Intermediate 2019 Swap Quarter 2 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	75,326
Average Price | $ / bbl	61.53
West Texas Intermediate 2019 Swap Quarter 3 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	72,279
Average Price | $ / bbl	61.57
West Texas Intermediate 2019 Swap Quarter 4 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	69,480
Average Price | $ / bbl	61.61
West Texas Intermediate 2019 [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	295,752
Average Price | $ / bbl	61.54
West Texas Intermediate 2020 Swap Quarter 1
Derivative [Line Items]
Volume (in Bbls) | bbl	66,914
Average Price | $ / bbl	53.50
West Texas Intermediate 2020 Swap Quarter 2
Derivative [Line Items]
Volume (in Bbls) | bbl	64,477
Average Price | $ / bbl	53.50
West Texas Intermediate 2020 Swap Quarter 3
Derivative [Line Items]
Volume (in Bbls) | bbl	62,251
Average Price | $ / bbl	53.50
West Texas Intermediate 2020 Swap Quarter 4
Derivative [Line Items]
Volume (in Bbls) | bbl	60,224
Average Price | $ / bbl	53.50
West Texas Intermediate 2020
Derivative [Line Items]
Volume (in Bbls) | bbl	253,866
Average Price | $ / bbl	53.50
West Texas Intermediate [Member]
Derivative [Line Items]
Volume (in Bbls) | bbl	1,047,001
NYMEX 2017 Swap Quarter 3 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	271,368
Average Price | $ / MMBTU	5.45
NYMEX 2017 Swap Quarter 4 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	257,234
Average Price | $ / MMBTU	5.45
NYMEX 2017 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	528,602
Average Price | $ / MMBTU	5.45
NYMEX 2018 Swap Quarter 1 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	260,841
Average Price | $ / MMBTU	3.18
NYMEX 2018 Swap Quarter 2 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	248,018
Average Price | $ / MMBTU	3.18
NYMEX 2018 Swap Quarter 3 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	235,810
Average Price | $ / MMBTU	3.18
NYMEX 2018 Swap Quarter 4 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	225,208
Average Price | $ / MMBTU	3.18
NYMEX 2018 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	969,877
Average Price | $ / MMBTU	3.18
NYMEX 2019 Swap Quarter 1 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	224,303
Average Price | $ / MMBTU	3.10
NYMEX 2019 Swap Quarter 2 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	214,186
Average Price | $ / MMBTU	3.10
NYMEX 2019 Swap Quarter 3 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	205,533
Average Price | $ / MMBTU	3.10
NYMEX 2019 Swap Quarter 4 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	197,455
Average Price | $ / MMBTU	3.10
NYMEX 2019 [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	841,477
Average Price | $ / MMBTU	3.10
NYMEX 2020 Swap Quarter 1
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	188,696
Average Price | $ / MMBTU	2.85
NYMEX 2020 Swap Quarter 2
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	176,946
Average Price | $ / MMBTU	2.85
NYMEX 2020 Swap Quarter 3
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	170,637
Average Price | $ / MMBTU	2.85
NYMEX 2020 Swap Quarter 4
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	164,747
Average Price | $ / MMBTU	2.85
NYMEX 2020
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	701,026
Average Price | $ / MMBTU	2.85
NYMEX [Member]
Derivative [Line Items]
Volume (in MMBtu) | MMBTU	3,040,982