XML 82 R65.htm IDEA: XBRL DOCUMENT
v3.22.4

Fair Value Measurements - Summary of Changes in the Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) $ in Millions | 3 Months Ended
--- | ---
Dec. 31, 2020 USD ($)
Fair Value Disclosures [Abstract] |
Consideration paid to sellers based on financial performance | $ 2.7

X
- Definition Business combinations additional consideration paid to sellers. + References No definition available. + Details
Name: | forr_BusinessCombinationsAdditionalConsiderationPaidToSellers
Namespace Prefix: | forr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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