Price-Risk Management Price-Risk Management (Details) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 22, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) MMBTU $ / MMBTU $ / Boe bbl	Dec. 31, 2015 USD ($)
Derivative [Line Items]
Receivables for Settled Derivatives | $		$ 400	$ 2,200
Payables for Settled Derivatives | $		1,800	400
Derivative, Fair Value, Net | $		(16,400)	(100)
Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset | $		500	5,100
Other Noncurrent Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset | $		0	2,600
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability | $		15,800	5,100
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability | $		1,000	2,800
Predecessor [Member]
Derivative [Line Items]
Gain (Loss) on Price Risk Derivatives, Net | $				$ 200
Cash Received (Paid) On Settlements of Derivative Contracts | $	$ 0			$ 2,544
Successor [Member]
Derivative [Line Items]
Gain (Loss) on Price Risk Derivatives, Net | $		(19,700)	17,900
Cash Received (Paid) On Settlements of Derivative Contracts | $		$ (1,928)	$ (1,411)
Swap [Member] | First Quarter 2018 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			151,000
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.80
Swap [Member] | First Quarter 2018 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			5,238,000
Derivative, Swap Type, Average Fixed Price			3.42
Swap [Member] | First Quarter 2018 [Member] | Successor [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl			126,000
Derivative, Swap Type, Average Fixed Price			24.78
Swap [Member] | Second Quarter 2018 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			140,400
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.57
Swap [Member] | Second Quarter 2018 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			8,245,000
Derivative, Swap Type, Average Fixed Price			2.86
Swap [Member] | Second Quarter 2018 [Member] | Successor [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl			118,200
Derivative, Swap Type, Average Fixed Price			24.78
Swap [Member] | Third Quarter 2018 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			130,400
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.40
Swap [Member] | Third Quarter 2018 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			8,014,000
Derivative, Swap Type, Average Fixed Price			2.88
Swap [Member] | Third Quarter 2018 [Member] | Successor [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl			112,200
Derivative, Swap Type, Average Fixed Price			24.78
Swap [Member] | Fourth Quarter 2018 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			122,800
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.23
Swap [Member] | Fourth Quarter 2018 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			7,976,000
Derivative, Swap Type, Average Fixed Price			2.96
Swap [Member] | Fourth Quarter 2018 [Member] | Successor [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl			148,200
Derivative, Swap Type, Average Fixed Price			24.78
Swap [Member] | First Quarter 2019 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			97,200
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.40
Swap [Member] | First Quarter 2019 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			6,016,000
Derivative, Swap Type, Average Fixed Price			3.07
Swap [Member] | Second Quarter 2019 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			92,700
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.32
Swap [Member] | Second Quarter 2019 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			6,060,000
Derivative, Swap Type, Average Fixed Price			2.83
Swap [Member] | Third Quarter 2019 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			88,500
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.39
Swap [Member] | Third Quarter 2019 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			5,550,000
Derivative, Swap Type, Average Fixed Price			2.84
Swap [Member] | Fourth Quarter 2019 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			84,500
Derivative, Swap Type, Average Fixed Price | $ / Boe			52.30
Swap [Member] | Fourth Quarter 2019 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			5,966,000
Derivative, Swap Type, Average Fixed Price			2.84
Swap [Member] | First Quarter 2020 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			51,000
Derivative, Swap Type, Average Fixed Price | $ / Boe			51.49
Swap [Member] | First Quarter 2020 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			5,370,000
Derivative, Swap Type, Average Fixed Price			2.83
Swap [Member] | Second Quarter 2020 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			49,250
Derivative, Swap Type, Average Fixed Price | $ / Boe			51.46
Swap [Member] | Second Quarter 2020 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			1,170,000
Derivative, Swap Type, Average Fixed Price			2.86
Swap [Member] | Third Quarter 2020 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			47,500
Derivative, Swap Type, Average Fixed Price | $ / Boe			51.42
Swap [Member] | Third Quarter 2020 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			1,170,000
Derivative, Swap Type, Average Fixed Price			2.86
Swap [Member] | Fourth Quarter 2020 [Member] | Successor [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			46,500
Derivative, Swap Type, Average Fixed Price | $ / Boe			51.40
Swap [Member] | Fourth Quarter 2020 [Member] | Successor [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			1,170,000
Derivative, Swap Type, Average Fixed Price			2.86
Basis Swap [Member] | First Quarter 2018 [Member] | Successor [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			5,105,000
Basis Differential Derivative Swap			0.11
Basis Swap [Member] | First Quarter 2018 [Member] | Successor [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			20,000
Basis Differential Derivative Swap			4.06
Basis Swap [Member] | Second Quarter 2018 [Member] | Successor [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			6,795,000
Basis Differential Derivative Swap			0.04
Basis Swap [Member] | Second Quarter 2018 [Member] | Successor [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			30,000
Basis Differential Derivative Swap			4.06
Basis Swap [Member] | Third Quarter 2018 [Member] | Successor [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			3,020,000
Basis Differential Derivative Swap			0.03
Basis Swap [Member] | Third Quarter 2018 [Member] | Successor [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			30,000
Basis Differential Derivative Swap			4.06
Basis Swap [Member] | Fourth Quarter 2018 [Member] | Successor [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			2,730,000
Basis Differential Derivative Swap			0.09
Basis Swap [Member] | Fourth Quarter 2018 [Member] | Successor [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl			30,000
Basis Differential Derivative Swap			4.06
Basis Swap [Member] | First Quarter 2019 [Member] | Successor [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU			750,000
Basis Differential Derivative Swap			0.11