Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
Apr. 23, 2021	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Estimated amount of cancellation of debt income		$ 1,266.0
Reversal of uncertain tax position reserve and offsetting valuation allowance for swiss tax reform	$ 187.0

Reversal of uncertain tax position reserve and offsetting valuation allowance.

No definition available.

Name:	do_ReversalOfUncertainTaxPositionReserveAndOffsettingValuationAllowance
Namespace Prefix:	do_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration