Income taxes - Changes in Uncertain Tax Positions (Detail) $ in Millions	6 Months Ended
Jun. 30, 2023 USD ($)
Unrecognized tax benefits:
Deferred income tax expense benefit non cash	$ 1.0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

Name:	us-gaap_ReconciliationOfUnrecognizedTaxBenefitsExcludingAmountsPertainingToExaminedTaxReturnsRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration