| Property, plant and equipment |
Property, plant and equipment in service and under construction, and related accumulated depreciation and amortization, as of December 31, 2025 and 2024, were as follows: | | | | | | | | | | | | | | | | | | | December 31, | Useful Lives (Years) | | 2025 | | 2024 | | (Dollars in thousands) | | | | | | | Land | N/A | | $ | 44,257 | | | $ | 41,737 | | | | | | | | | Leasehold and land improvements | 1-30 | | 321,542 | | | 317,038 | | | Communications infrastructure assets | 7-30 | | 696,918 | | | 667,401 | | | | | | | | | | | | | | | Other operating assets and equipment | 5-8 | | 2,866 | | | 2,768 | | | System development | 3-5 | | 3,032 | | | 2,743 | | | Work in process | N/A | | 10,391 | | | 5,958 | | | Total property, plant and equipment, gross | | | 1,079,006 | | | 1,037,645 | | | Accumulated depreciation and amortization | | | (690,007) | | | (653,624) | | | Total property, plant and equipment, net | | | $ | 388,999 | | | $ | 384,021 | |
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