RECEIVABLES, CONTRACT ASSETS, AND DEFERRED REVENUE RECEIVABLES, CONTRACT ASSETS, AND DEFERRED REVENUE - Additional Information (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($)
Receivables [Abstract]
Revenue recognized during the period that was included in deferred revenue	$ 234.4

Contract with Customer, Liability, Revenue Recognized, Including Opening Balance

No definition available.

Name:	pega_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance
Namespace Prefix:	pega_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration