iAnthus Capital Holdings, Inc. Annual report [Section 13 and 15(d), not S-K Item 405]

Financial Instruments - Summary of Fair Value Hierarchy of Company's Financial Assets and Financial Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Financial liabilities
Derivative Liability Statement Of Financial Position Extensible Enumeration Not Disclosed Flag	true	true
Fair Value, Recurring \| Level 2 [Member]
Financial liabilities
Contingent consideration payable	$ 0	$ 0
Fair Value, Recurring \| Level 3 [Member]
Financial liabilities
Contingent consideration payable	3,407
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Recurring
Financial liabilities
Contingent consideration payable	3,407	3,127
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Recurring \| Level 1 [Member]
Financial liabilities
Contingent consideration payable	0	0
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Recurring \| Level 3 [Member]
Financial liabilities
Contingent consideration payable		3,127
Other Long-term Investments [Member] \| Fair Value, Recurring
Financial assets
Long term investments - other	842	863
Other Long-term Investments [Member] \| Fair Value, Recurring \| Level 1 [Member]
Financial assets
Long term investments - other	2	10
Other Long-term Investments [Member] \| Fair Value, Recurring \| Level 2 [Member]
Financial assets
Long term investments - other	0	0
Other Long-term Investments [Member] \| Fair Value, Recurring \| Level 3 [Member]
Financial assets
Long term investments - other	$ 840	$ 853