v3.25.2
Long-term debt: - Limitations under the Indentures (Details)
6 Months Ended
Jun. 30, 2025
USD ($)
Apr. 11, 2025
May 02, 2024
Long-term debt      
Amount unrestricted and permitted for investment payments $ 295,600,000    
Indentures | Minimum      
Long-term debt      
Consolidated leverage ratio 1    
Consolidated secured leverage ratio 1    
Fixed charge coverage ratio 1    
Indebtedness that may occur $ 1    
Indentures | Maximum      
Long-term debt      
Consolidated leverage ratio 6    
Consolidated secured leverage ratio 4    
Fixed charge coverage ratio 2    
2027 Notes Indentures | Minimum      
Long-term debt      
Consolidated leverage ratio 1    
Consolidated secured leverage ratio 4    
Fixed charge coverage ratio 2    
2027 Notes Indentures | Maximum      
Long-term debt      
Consolidated leverage ratio 6    
2032 Notes Indenture | Minimum      
Long-term debt      
Consolidated leverage ratio 1    
Fixed charge coverage ratio 2    
2032 Notes Indenture | Maximum      
Long-term debt      
Consolidated leverage ratio 6    
Consolidated secured leverage ratio 4    
Issuance Of Additional Class Notes [Member] | Existing IPv4 Notes | Minimum      
Long-term debt      
Consolidated leverage ratio     1
Issuance Of Additional Class Notes [Member] | Existing IPv4 Notes | Maximum      
Long-term debt      
Consolidated leverage ratio     6.1
Issuance Of Additional Class Notes [Member] | IPv4 New Notes | Minimum      
Long-term debt      
Consolidated leverage ratio   1  
Issuance Of Additional Class Notes [Member] | IPv4 New Notes | Maximum      
Long-term debt      
Consolidated leverage ratio   7.25  
Substitute New Ipv4 Addresses [Member] | Existing IPv4 Notes | Minimum      
Long-term debt      
Consolidated leverage ratio   1 1
Substitute New Ipv4 Addresses [Member] | Existing IPv4 Notes | Maximum      
Long-term debt      
Consolidated leverage ratio   7.25 6.1
Dispose Of Ipv Addresses Owned By Ipv Issuer Member Dispose Of Ipv Addresses Owned By Ipv Issuer [Member] | Existing IPv4 Notes | Minimum      
Long-term debt      
Consolidated leverage ratio     1
Dispose Of Ipv Addresses Owned By Ipv Issuer Member Dispose Of Ipv Addresses Owned By Ipv Issuer [Member] | Existing IPv4 Notes | Maximum      
Long-term debt      
Consolidated leverage ratio     7.1
Dispose Of Ipv Addresses Owned By Ipv Issuer Member Dispose Of Ipv Addresses Owned By Ipv Issuer [Member] | IPv4 New Notes | Minimum      
Long-term debt      
Consolidated leverage ratio   1  
Dispose Of Ipv Addresses Owned By Ipv Issuer Member Dispose Of Ipv Addresses Owned By Ipv Issuer [Member] | IPv4 New Notes | Maximum      
Long-term debt      
Consolidated leverage ratio   7.25