Shareholders' Equity (Deficit) - Summary of Vested and Unvested Share-Based Awards Activity (Parenthetical) (Detail) shares in Thousands	Dec. 31, 2021 $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based Awards, vested or expected to vest \| shares	639
Share-based Awards , vested or expected to vest, weighted average price \| $ / shares	$ 213.70

Share-based compensation arrangement by share-based payment award, equity other than options, vested and expected to vest, outstanding, number.

No definition available.

Name:	msci_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber
Namespace Prefix:	msci_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant