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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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