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Derivative Instruments - Schedule of Outstanding Commodity Derivative Instruments (Detail) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 01, 2019 MMBTU $ / bbl MBbls	Dec. 31, 2018 USD ($) MMBTU $ / bbl $ / MMBTU MBbls
Derivative [Line Items]
Fair value assets (liability) | $		$ 106,771
NYMEX WTI | Crude oil | 2019 Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		5,690.5
Average swap price (in dollars per barrel / dollars per btu)		53.63
Fair value assets (liability) | $		$ 33,827
NYMEX WTI | Crude oil | 2019 Two-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		3,937.5
Average floor price (in dollars per barrel / dollars per btu)		58.47
Average ceiling price (in dollars per barrel / dollars per btu)		77.03
Fair value assets (liability) | $		$ 48,320
NYMEX WTI | Crude oil | 2019 Three-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		3,702
Average sub-floor price (in dollars per barrel / dollars per btu)		40.49
Average floor price (in dollars per barrel / dollars per btu)		50.94
Average ceiling price (in dollars per barrel / dollars per btu)		67.97
Fair value assets (liability) | $		$ 16,528
NYMEX WTI | Crude oil | 2020 Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		403
Average swap price (in dollars per barrel / dollars per btu)		53.47
Fair value assets (liability) | $		$ 1,928
NYMEX WTI | Crude oil | 2020 Two-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		341
Average floor price (in dollars per barrel / dollars per btu)		58.18
Average ceiling price (in dollars per barrel / dollars per btu)		77.65
Fair value assets (liability) | $		$ 3,982
NYMEX WTI | Crude oil | 2020 Three-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		310
Average sub-floor price (in dollars per barrel / dollars per btu)		40.00
Average floor price (in dollars per barrel / dollars per btu)		50.50
Average ceiling price (in dollars per barrel / dollars per btu)		67.10
Fair value assets (liability) | $		$ 1,035
NYMEX WTI | Subsequent Event | Crude oil | 2019 Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	5,690.5
Average swap price (in dollars per barrel / dollars per btu)	53.63
NYMEX WTI | Subsequent Event | Crude oil | 2019 Two-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	4,454.5
Average floor price (in dollars per barrel / dollars per btu)	58.01
Average ceiling price (in dollars per barrel / dollars per btu)	74.77
NYMEX WTI | Subsequent Event | Crude oil | 2019 Three-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	4,008
Average sub-floor price (in dollars per barrel / dollars per btu)	40.45
Average floor price (in dollars per barrel / dollars per btu)	51.40
Average ceiling price (in dollars per barrel / dollars per btu)	67.13
NYMEX WTI | Subsequent Event | Crude oil | 2020 Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	403
Average swap price (in dollars per barrel / dollars per btu)	53.47
NYMEX WTI | Subsequent Event | Crude oil | 2020 Two-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	372
Average floor price (in dollars per barrel / dollars per btu)	58.08
Average ceiling price (in dollars per barrel / dollars per btu)	76.05
NYMEX WTI | Subsequent Event | Crude oil | 2020 Three-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	1,224
Average sub-floor price (in dollars per barrel / dollars per btu)	40.00
Average floor price (in dollars per barrel / dollars per btu)	55.55
Average ceiling price (in dollars per barrel / dollars per btu)	60.11
NYMEX WTI | Subsequent Event | Crude oil | 2021 Three-way Collars
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	62
Average sub-floor price (in dollars per barrel / dollars per btu)	40.00
Average floor price (in dollars per barrel / dollars per btu)	57.37
Average ceiling price (in dollars per barrel / dollars per btu)	57.37
NYMEX WTI-ICE BRENT | Crude oil | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		424
Average swap price (in dollars per barrel / dollars per btu)		9.68
Fair value assets (liability) | $		$ 673
NYMEX WTI-ICE BRENT | Subsequent Event | Crude oil | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	424
NYMEX WTI-ICE BRENT | Subsequent Event | Natural gas | 2019 Basis Swaps
Derivative [Line Items]
Average swap price (in dollars per barrel / dollars per btu)	9.68
Midland-NYMEX WTI | Crude oil | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls		605
Average swap price (in dollars per barrel / dollars per btu)		7.19
Fair value assets (liability) | $		$ (865)
Midland-NYMEX WTI | Subsequent Event | Crude oil | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	755
Midland-NYMEX WTI | Subsequent Event | Natural gas | 2019 Basis Swaps
Derivative [Line Items]
Average swap price (in dollars per barrel / dollars per btu)	6.83
Houston NYMEX WTI | Subsequent Event | Crude oil | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of oil barrels (in bbl) | MBbls	549
Houston NYMEX WTI | Subsequent Event | Natural gas | 2019 Basis Swaps
Derivative [Line Items]
Average swap price (in dollars per barrel / dollars per btu)	4.55
NYMEX HH | Natural gas | 2019 Swaps
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU		6,446,000
Average swap price (in dollars per barrel / dollars per btu) | $ / MMBTU		3.15
Fair value assets (liability) | $		$ 1,303
NYMEX HH | Subsequent Event | Natural gas | 2019 Swaps
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	9,196,000
Average swap price (in dollars per barrel / dollars per btu)	3.08
IF NNG VENTURA-NYMEX | Natural gas | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU		4,525,000
Average swap price (in dollars per barrel / dollars per btu)		0.02
Fair value assets (liability) | $		$ 40
IF NNG VENTURA-NYMEX | Subsequent Event | Natural gas | 2019 Basis Swaps
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	4,820,000
Average swap price (in dollars per barrel / dollars per btu)	0.05

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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