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Number of tranches in a share based payment arrangement.

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Represents the performance cycle of each tranche in a share based payment arrangement.

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- Definition

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

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option 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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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Percentage of vesting of award under share-based payment arrangement.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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STOCK-BASED COMPENSATION - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($) tranche component shares	Dec. 31, 2019 USD ($) shares	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 7,451	$ 10,201
Exercise of employee stock options, net of shares withheld for employee taxes (in shares) \| shares	0
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of units vested	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of units vested	200.00%
Contract Drilling Services Operating Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,800	2,400
Selling, General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	5,400	$ 7,800
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 300
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period over which awards expire	10 years
Awards granted (in shares) \| shares	0	0
Stock-based compensation expense	$ 318	$ 571
Exercise of employee stock options, net of shares withheld for employee taxes (in shares) \| shares	0
Total intrinsic value of options exercised		300
Unrecognized compensation cost related to stock options	$ 900
Weighted average period over which unrecognized compensation cost is expected to be recognized	1 year
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 6,011	7,370
Weighted average period over which unrecognized compensation cost is expected to be recognized	2 years 7 months 6 days
Vesting period	3 years		4 years
Unrecognized compensation cost related to non-option awards	$ 41,600
Restricted Stock Awards \| 2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares) \| shares	631,166
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,122	$ 2,260
Weighted average period over which unrecognized compensation cost is expected to be recognized	2 years 7 months 6 days
Vesting period	3 years
Unrecognized compensation cost related to non-option awards	$ 14,600
Performance components \| component	2
Performance Share Units \| 2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares) \| shares	312,600
Performance Share Units - First Component
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period over which awards expire	3 years
Performance Share Units - Second Component
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period over which awards expire	3 years
Number of tranches \| tranche	3
Performance cycle period of each tranche	1 year