Price-Risk Management Price-Risk Management (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) MMBTU $ / MMBTU $ / Boe bbl	Dec. 31, 2017 USD ($)
Derivative [Line Items]
Gain (Loss) on Price Risk Derivatives, Net | $	$ (9,800)	$ 17,900
Cash Received (Paid) On Settlements of Derivative Contracts | $	(19,677)	(1,411)
Receivables for Settled Derivatives | $	700	2,200
Payables for Settled Derivatives | $	2,200	400
Derivative, Fair Value, Net | $	13,000	(100)
Other Current Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset | $	15,300	5,100
Other Noncurrent Assets [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset | $	4,300	2,600
Other Current Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability | $	2,800	5,100
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability | $	$ 3,700	$ 2,800
Swap [Member] | First Quarter 2019 [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	124,200
Derivative, Swap Type, Average Fixed Price | $ / Boe	54.95
Swap [Member] | First Quarter 2019 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	5,693,000
Derivative, Swap Type, Average Fixed Price	3.11
Swap [Member] | First Quarter 2019 [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl	180,000
Derivative, Swap Type, Average Fixed Price | $ / Boe	27.93
Swap [Member] | Second Quarter 2019 [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	134,700
Derivative, Swap Type, Average Fixed Price | $ / Boe	57.08
Swap [Member] | Second Quarter 2019 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	12,130,000
Derivative, Swap Type, Average Fixed Price	2.80
Swap [Member] | Second Quarter 2019 [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl	180,000
Derivative, Swap Type, Average Fixed Price | $ / Boe	27.93
Swap [Member] | Third Quarter 2019 [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	130,500
Derivative, Swap Type, Average Fixed Price | $ / Boe	57.27
Swap [Member] | Third Quarter 2019 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	11,990,000
Derivative, Swap Type, Average Fixed Price	2.80
Swap [Member] | Third Quarter 2019 [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl	180,000
Derivative, Swap Type, Average Fixed Price | $ / Boe	27.93
Swap [Member] | Fourth Quarter 2019 [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	126,500
Derivative, Swap Type, Average Fixed Price | $ / Boe	57.37
Swap [Member] | Fourth Quarter 2019 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	9,646,000
Derivative, Swap Type, Average Fixed Price	2.86
Swap [Member] | Fourth Quarter 2019 [Member] | Natural Gas Liquid Derivative [Member]
Derivative [Line Items]
Future NGL Production Hedged in Bbls (Energy Item Type) | bbl	180,000
Derivative, Swap Type, Average Fixed Price | $ / Boe	27.93
Swap [Member] | First Quarter 2020 [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	103,800
Derivative, Swap Type, Average Fixed Price | $ / Boe	56.28
Swap [Member] | First Quarter 2020 [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] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	100,350
Derivative, Swap Type, Average Fixed Price | $ / Boe	56.38
Swap [Member] | Second Quarter 2020 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	3,688,000
Derivative, Swap Type, Average Fixed Price	2.76
Swap [Member] | Third Quarter 2020 [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	56.49
Swap [Member] | Third Quarter 2020 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	3,585,000
Derivative, Swap Type, Average Fixed Price	2.76
Swap [Member] | Fourth Quarter 2020 [Member] | Oil Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	72,000
Derivative, Swap Type, Average Fixed Price | $ / Boe	52.29
Swap [Member] | Fourth Quarter 2020 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	3,362,000
Derivative, Swap Type, Average Fixed Price	2.77
Collar Contracts [Member] | First Quarter 2019 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	3,337,500
Derivative, Average Floor Price	3.34
Derivative, Average Cap Price	3.82
Collar Contracts [Member] | Second Quarter 2019 [Member] | Natural Gas Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	300,000
Derivative, Average Floor Price	2.90
Derivative, Average Cap Price	3.15
Basis Swap [Member] | First Quarter 2019 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	9,047,500
Basis Differential Derivative Swap	(0.05)
Basis Swap [Member] | First Quarter 2019 [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	30,000
Basis Differential Derivative Swap | $ / Boe	4.65
Basis Swap [Member] | Second Quarter 2019 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	14,477,500
Basis Differential Derivative Swap	0.05
Basis Swap [Member] | Second Quarter 2019 [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	45,000
Basis Differential Derivative Swap | $ / Boe	4.65
Basis Swap [Member] | Third Quarter 2019 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	14,625,000
Basis Differential Derivative Swap	0.04
Basis Swap [Member] | Third Quarter 2019 [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	45,000
Basis Differential Derivative Swap | $ / Boe	4.65
Basis Swap [Member] | Fourth Quarter 2019 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	14,625,000
Basis Differential Derivative Swap	(0.02)
Basis Swap [Member] | Fourth Quarter 2019 [Member] | Oil Basis Derivative [Member]
Derivative [Line Items]
Portion of Future Oil and Gas Production Being Hedged | bbl	45,000
Basis Differential Derivative Swap | $ / Boe	4.65
Basis Swap [Member] | First Quarter 2020 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	11,739,000
Basis Differential Derivative Swap	(0.03)
Basis Swap [Member] | Second Quarter 2020 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	11,739,000
Basis Differential Derivative Swap	(0.04)
Basis Swap [Member] | Third Quarter 2020 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	11,868,000
Basis Differential Derivative Swap	(0.03)
Basis Swap [Member] | Fourth Quarter 2020 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	11,868,000
Basis Differential Derivative Swap	(0.04)
Basis Swap [Member] | First Quarter 2021 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	5,400,000
Basis Differential Derivative Swap	(0.004)
Basis Swap [Member] | Second Quarter 2021 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	5,460,000
Basis Differential Derivative Swap	(0.004)
Basis Swap [Member] | Third Quarter 2021 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	5,520,000
Basis Differential Derivative Swap	(0.004)
Basis Swap [Member] | Fourth Quarter 2021 [Member] | Natural Gas Basis Derivative [Member]
Derivative [Line Items]
Future Gas Production Hedged in MMBtu (Energy Item Type) | MMBTU	5,520,000
Basis Differential Derivative Swap	(0.004)