NOTES RECEIVABLE (Details) - Secured Promissory Note - USD ($) $ in Millions			3 Months Ended
	Dec. 09, 2024	Mar. 31, 2023	Mar. 31, 2025	Mar. 31, 2024
Greenbrook TMS Inc
NOTES RECEIVABLE
Principal amount of notes receivable		$ 6.0
Term of notes receivable		4 years
Loan receivable forgiven by the entity	$ 3.6
Greenbrook TMS Inc | Secured Overnight Financing Rate
NOTES RECEIVABLE
Interest rate (as a percent)		7.65%
Success TMS | Other income, net
NOTES RECEIVABLE
Interest income recognized			$ 0.0	$ 0.2