XML 91 R77.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Share-Based Compensation - Schedule of Fair Value of Stock Option Award Granted Estimated on Date of Grant Using the Black-Scholes-Merton Option Pricing Model (Parenthetical) (Detail) - shares | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |  |
Awarded, Options | 0 | 0

X
- Definition Net number of share options (or share units) awarded during the period. + References No definition available. + Details
Name: | prdo_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAwardedInPeriod
Namespace Prefix: | prdo_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration