v3.25.2
ALLOWANCE FOR CREDIT LOSSES (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Financing Receivable, Allowance for Credit Loss [Roll Forward]    
Beginning balance $ 22.8 $ 23.2
Current-period provision for expected credit losses 16.9 17.0
Write-offs charged against the allowance (12.5) (17.8)
Ending balance 27.2 22.4
CoStar    
Financing Receivable, Allowance for Credit Loss [Roll Forward]    
Beginning balance 6.1 9.7
Current-period provision for expected credit losses 6.8 7.1
Write-offs charged against the allowance (5.2) (9.5)
Ending balance 7.7 7.3
Information Services    
Financing Receivable, Allowance for Credit Loss [Roll Forward]    
Beginning balance 3.9 2.5
Current-period provision for expected credit losses 0.6 0.7
Write-offs charged against the allowance (1.0) (0.7)
Ending balance 3.5 2.5
Multifamily    
Financing Receivable, Allowance for Credit Loss [Roll Forward]    
Beginning balance 9.4 7.3
Current-period provision for expected credit losses 6.5 6.5
Write-offs charged against the allowance (5.0) (4.8)
Ending balance 10.9 9.0
LoopNet    
Financing Receivable, Allowance for Credit Loss [Roll Forward]    
Beginning balance 3.0 2.7
Current-period provision for expected credit losses 2.0 2.5
Write-offs charged against the allowance (1.6) (2.9)
Ending balance 3.4 2.3
Other Revenues    
Financing Receivable, Allowance for Credit Loss [Roll Forward]    
Beginning balance 0.4 1.0
Current-period provision for expected credit losses 1.0 0.2
Write-offs charged against the allowance 0.3 0.1
Ending balance $ 1.7 $ 1.3