REVENUE - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,211,653	$ 1,017,517	$ 911,383
Perpetual license
Disaggregation of Revenue [Line Items]
Total revenue	32,172	28,558	80,015
Subscription license
Disaggregation of Revenue [Line Items]
Total revenue	336,248	266,352	199,433
Subscription services
Disaggregation of Revenue [Line Items]
Total revenue	621,223	504,977	414,326
Subscription
Disaggregation of Revenue [Line Items]
Total revenue	957,471	771,329	613,759
Consulting
Disaggregation of Revenue [Line Items]
Total revenue	222,010	217,630	217,609
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	368,420	294,910	279,448
Revenue recognized at a point in time | Perpetual license
Disaggregation of Revenue [Line Items]
Total revenue	32,172	28,558	80,015
Revenue recognized at a point in time | Subscription license
Disaggregation of Revenue [Line Items]
Total revenue	336,248	266,352	199,433
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue	843,233	722,607	631,935
Revenue recognized over time | Maintenance
Disaggregation of Revenue [Line Items]
Total revenue	320,257	296,709	280,580
Revenue recognized over time | Pega Cloud
Disaggregation of Revenue [Line Items]
Total revenue	300,966	208,268	133,746
Revenue recognized over time | Consulting
Disaggregation of Revenue [Line Items]
Total revenue	$ 222,010	$ 217,630	$ 217,609