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Share-based Compensation Arrangement by Share-based Payment Award, Annual Increase in Number of Shares Authorized for Issuance

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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