Quarterly report [Sections 13 or 15(d)]

Leases - Additional Information (Detail)

v3.26.1
Leases - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Lessee, Lease, Description [Line Items]        
Operating lease expense $ 1.9 $ 1.9 $ 3.8 $ 3.8
Operating Cash Flows From Operating Lease 1.8 1.8 $ 3.7 3.4
Minimum [Member]        
Lessee, Lease, Description [Line Items]        
Sublease lease term     1 year  
Maximum [Member]        
Lessee, Lease, Description [Line Items]        
Sublease lease term     15 years  
Location, Statement of Income, Balance [Axis]: ithuf:InterestAndOtherIncomeExpense | Sublease [Member]        
Lessee, Lease, Description [Line Items]        
Sublease Income $ 0.2 $ 0.2 $ 0.4 $ 0.5