XML 65 R111.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Change Recognized in Other Comprehesinve Loss (Details) - USD ($) $ in Thousands | 2 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2019 | Dec. 31, 2018
Retirement Benefits [Abstract] |  |  |
Net loss (gain) | $ 578 | $ 2,526 | $ (356)

X
- Definition Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising during Period, Net of Curtailment Gain, Before Tax + References No definition available. + Details
Name: | sons_OtherComprehensiveIncomeLossDefinedBenefitPlanGainLossArisingduringPeriodNetofCurtailmentGainBeforeTax
Namespace Prefix: | sons_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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