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Equity-Based Compensation - Additional Information (Detail) |  |  | 1 Months Ended | 11 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jan. 01, 2021 shares | Nov. 19, 2020 shares | Dec. 31, 2020 USD ($) $ / shares shares | Jun. 30, 2020 USD ($) | May 31, 2017 | Nov. 19, 2020 USD ($) $ / shares shares | Dec. 31, 2020 USD ($) day shares | Dec. 31, 2019 USD ($) $ / shares | Dec. 31, 2018 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Number of shares available for grant (in shares) | shares |  |  | 16,050,000 |  |  |  | 16,050,000 |  |
Equity-based compensation |  |  | $ 270,000 |  |  | $ 31,315,000 |  | $ 33,607,000 | $ 29,273,000
Stock-based compensation expense |  |  | $ 270,000 |  |  | 31,315,000 |  | 33,607,000 | 29,273,000
Associated tax benefit |  |  |  |  |  |  |  | 7,800,000 | 6,800,000
Restricted stock awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 3 years |  |
Stock-based compensation expense |  |  |  |  |  | $ 19,000,000.0 |  | 24,000,000.0 | 20,100,000
Fair value of awards vested |  |  |  |  |  |  | $ 47,300,000 | $ 14,600,000 | $ 17,300,000
Weighted average grant date fair value of awards granted (in dollars per share) | $ / shares |  |  | $ 37.35 |  |  | $ 3.06 |  | $ 6.61 | $ 10.20
Accelerated recognition |  |  |  |  |  | $ 6,700,000 |  |  |
Performance share unit awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  |  | $ 11,200,000 |  | $ 9,000,000.0 | $ 8,500,000
Fair value of awards vested |  |  |  |  |  |  | $ 7,600,000 | $ 2,600,000 | $ 5,300,000
Weighted average grant date fair value of awards granted (in dollars per share) | $ / shares |  |  |  |  |  | $ 2.56 |  | $ 6.80 | $ 12.71
Accelerated recognition |  |  | $ 4,700,000 |  |  |  |  |  |
Right to received shares of common stock (in shares) | shares |  |  | 1 |  |  |  | 1 |  |
Number of trading days | day |  |  |  |  |  |  | 30 |  |
Performance share unit awards | Minimum |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 3 years |  |
PSU granted percentage of earnings (percent) |  |  | 0.00% |  |  | 0.00% |  |  |
Performance share unit awards | Maximum |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 4 years |  |
PSU granted percentage of earnings (percent) |  |  | 150.00% |  |  | 240.00% |  |  |
Phantom units |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Accelerated recognition |  |  | $ 700,000 |  |  | $ 1,100,000 |  |  |
Restricted unit awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 4 years |  |
Leverage Stock Unit Awards | Minimum |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 3 years |  |
Percentage Of LSU awards |  |  |  |  |  |  | 0.00% |  |
Leverage Stock Unit Awards | Maximum |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 4 years |  |
Percentage Of LSU awards |  |  |  |  |  |  | 300.00% |  |
2020 Incentive Compensation Program |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Compensation program payments made |  |  |  |  |  |  | $ 15,600,000 |  |
Incentive distribution expensed |  |  |  |  |  |  | 4,100,000 |  |
Equity-based compensation |  |  |  |  |  |  | 400,000 |  |
Employee related reorganization charges |  |  | (4,300,000) |  |  |  |  |  |
2020 Incentive Compensation Program | Officers and Senior Employees |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Incentive distribution, distribution capitalized as prepaid expense |  |  |  |  |  |  | 8,800,000 |  |
June 2020 Incentive Payment |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Excess of cash retention payments over amounts already recognized |  |  |  | $ 2,100,000 |  |  |  |  |
June 2020 Incentive Payment | All Other Employees |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Compensation program payments made |  |  |  |  |  |  | $ 2,700,000 |  |
OMP GP |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  | 200,000 |  |  | 900,000 |  | $ 200,000 | $ 300,000
OMP GP | Restricted unit awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 10 years |  |  |  |
Percentage of outstanding units (percent) |  |  |  |  | 8.00% |  |  |  |
OMP LTIP |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  |  |  | 1 year |  |
OMP LTIP | Restricted unit awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Unrecognized expense |  |  | $ 10,000.00 |  |  |  | $ 10,000.00 |  |
Unrecognized expense recognition period |  |  |  |  |  |  | 1 month 6 days |  |
Stock-based compensation expense |  |  |  |  |  | $ 200,000 |  | 400,000 | $ 400,000
Fair value of awards vested |  |  |  |  |  |  | $ 300,000 | $ 300,000 |
Weighted average grant date fair value of awards granted (in dollars per share) | $ / shares |  |  | $ 0 |  |  | $ 16.69 |  | $ 18.57 | $ 17.55
Long Term Incentive Plan (LTIP) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Percentage of new equity at emergence |  | 10.00% |  |  |  |  |  |  |
Percentage of new equity at emergence, required to be allocated |  | 5.00% |  |  |  |  |  |  |
Number of shares available for grant (in shares) | shares |  | 2,402,402 | 2,793,360 |  |  | 2,402,402 | 2,793,360 |  |
Increase in common units that can be issued as percentage of units outstanding (percent) |  |  | 1.00% |  |  |  | 1.00% |  |
Long Term Incentive Plan (LTIP) | Restricted stock awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Unrecognized expense |  |  | $ 3,500,000 |  |  |  | $ 3,500,000 |  |
Unrecognized expense recognition period |  |  | 3 years |  |  |  |  |  |
Long Term Incentive Plan (LTIP) | Phantom units |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Unrecognized expense recognition period |  |  |  |  |  |  | 1 year 3 months 18 days |  |
Stock-based compensation expense |  |  |  |  |  | $ 1,500,000 | $ 200,000 | $ 2,500,000 | $ 500,000
Fair value of awards vested |  |  |  |  |  |  | $ 3,400,000 | $ 800,000 | $ 600,000
Weighted average grant date fair value of awards granted (in dollars per share) | $ / shares |  |  | $ 0 |  |  | $ 8.65 |  | $ 18.57 | $ 23.91
Fair market value equivalent of number of OMP common units (in shares) | shares |  |  | 1 |  |  |  | 1 |  |
Vesting period |  |  |  |  |  |  | 3 years |  |
Unrecognized compensation cost |  |  | $ 200,000 |  |  |  | $ 200,000 |  |
Subsequent Event | OMP LTIP |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Additional number of units authorized (in shares) | shares | 338,114 |  |  |  |  |  |  |  |

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