iAnthus Capital Holdings, Inc. Quarterly report [Sections 13 or 15(d)]

Financial Instruments - Summary of Fair Value Hierarchy of Company's Financial Assets and Financial Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Financial liabilities
Derivative Liability Statement Of Financial Position Extensible Enumeration Not Disclosed Flag	true	true
Fair Value Measurements Recurring Member
Financial liabilities
Contingent consideration payable	$ 3,726	$ 3,407
Fair Value Measurements Recurring Member \| Level 1 [Member]
Financial liabilities
Contingent consideration payable	0	0
Fair Value Measurements Recurring Member \| Level 2
Financial liabilities
Contingent consideration payable	0	0
Fair Value Measurements Recurring Member \| Level 3 [Member]
Financial liabilities
Contingent consideration payable	3,726	3,407
Other Long-term Investments [Member] \| Fair Value Measurements Recurring Member
Financial assets
Long term investments	878	842
Other Long-term Investments [Member] \| Fair Value Measurements Recurring Member \| Level 1 [Member]
Financial assets
Long term investments	0	2
Other Long-term Investments [Member] \| Fair Value Measurements Recurring Member \| Level 2
Financial assets
Long term investments	0	0
Other Long-term Investments [Member] \| Fair Value Measurements Recurring Member \| Level 3 [Member]
Financial assets
Long term investments	$ 878	$ 840