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

Quarterly report [Sections 13 or 15(d)]

Acquisitions - Additional Information (Detail)

Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025	Dec. 17, 2025	Dec. 30, 2024
Business Combination [Line Items]
Earn out payments, Description	On December 17, 2025, the Company entered into an amendment to the Cheetah Purchase Agreement with the Cheetah Seller, pursuant to which: (i) the payment schedule for the 2025 fiscal year Earn-Out (the "2025 Earn-Out") was amended and deferred as follows: (x) 20% of the 2025 Earn-Out was paid on April 15, 2026, (y) 40% of the 2025 Earn-Out was paid on October 15, 2026, and (z) 40% of the 2025 Earn-Out is payable on December 15, 2026 (collectively, the "Deferred Earn-Out Payments"); (ii) the Company agreed to pay the Cheetah Seller interest on the Deferred Earn-Out Payments at a rate of 6% per annum, which interest was paid in advance on April 15, 2026; and (iii) the Company agreed to pay additional consideration based on EBITDA generated by the Brand during the first quarter of 2028, which will be payable on June 15, 2028. On September 1, 2026, the Company entered into a second amendment to the Cheetah Purchase Agreement with the Cheetah Seller, pursuant to which the Company will no longer pay additional consideration on EBITDA generated by the Brand during the first quarter of 2028.
Business combination acquisition related costs	$ 0	$ 0
Cheetah Enterprises, Inc. [Member]
Business Combination [Line Items]
Purchased of assets					$ 3,500
Common shares issued for acquisition					1,500
Cash consideration payble for acquisitions					$ 1,200
Acquisition of financial liabilities fair value disclosure			$ 3,127
Deferred earn-out payments, interest rate				6.00%
Cheetah Enterprises, Inc. [Member] \| Preliminary Allocation [Member]
Business Combination [Line Items]
Acquisition of financial liabilities fair value disclosure	$ 3,100