Accrued Restructuring Costs - Additional Information (Detail) (Facility Closing, USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2010
Facility Closing
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 1.6
Lease expiration date	2013

Amounts charged or credited against earnings in the period for incurred or estimated costs associated with an exit plan or for changes in estimated costs associated with an exit plan from or disposal of business activities or restructurings pursuant to a duly authorized plan.

No definition available.

Name:	pega_RestructuringChargesCredits
Namespace Prefix:	pega_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration