| Goodwill and Intangible Assets Goodwill The changes in the net carrying amount of goodwill by operating segment were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | (Dollars in millions) | Advanced Electronics Solutions | | Elastomeric Material Solutions | | Other | | Total | | December 31, 2025 | $ | 51.7 | | | $ | 249.5 | | | $ | 2.2 | | | $ | 303.4 | | | | | | | | | | | | | | | | | | | | | | | | | | | Foreign currency translation adjustment | — | | | (2.3) | | | — | | | (2.3) | | | June 30, 2026 | $ | 51.7 | | | $ | 247.2 | | | $ | 2.2 | | | $ | 301.1 | |
Intangible Assets The carrying amount of intangible assets were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | June 30, 2026 | | December 31, 2025 | | (Dollars in millions) | Gross Carrying Amount | | | Accumulated Amortization | | Net Carrying Amount | | Gross Carrying Amount | | Accumulated Impairment | | Accumulated Amortization | | Net Carrying Amount | | Customer relationships | $ | 179.6 | | | | $ | 108.5 | | | $ | 71.1 | | | $ | 180.9 | | | $ | — | | | $ | 105.6 | | | $ | 75.3 | | | Technology | 78.4 | | | | 67.7 | | | 10.7 | | | 79.4 | | | — | | | 67.2 | | | 12.2 | | | Trademarks and trade names | 19.9 | | | | 8.5 | | | 11.4 | | | 20.1 | | | — | | | 8.3 | | | 11.8 | | | Total definite-lived intangible assets | 277.9 | | | | 184.7 | | | 93.2 | | | 280.4 | | | — | | | 181.1 | | | 99.3 | | | Indefinite-lived intangible asset | — | | | | — | | | — | | | 4.5 | | | 4.5 | | | — | | | — | | | Total intangible assets | $ | 277.9 | | | | $ | 184.7 | | | $ | 93.2 | | | $ | 284.9 | | | $ | 4.5 | | | $ | 181.1 | | | $ | 99.3 | |
In the table above, gross carrying amounts and accumulated amortization may differ from prior periods due to foreign exchange rate fluctuations. The amortization expense related to intangible assets was as follows: | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended | | Six Months Ended | | (Dollars in millions) | June 30, 2026 | | June 30, 2025 | | June 30, 2026 | | June 30, 2025 | | Amortization expense | $ | 2.6 | | | $ | 2.7 | | | $ | 5.3 | | | $ | 5.4 | |
The estimated future amortization expense is $5.3 million, $10.2 million, $8.0 million, $7.5 million, and $7.1 million in 2026, 2027, 2028, 2029, and 2030, respectively. These amounts could vary based on changes in foreign currency exchange rates. The weighted average amortization period as of June 30, 2026, by intangible asset class, is presented in the table below: | | | | | | | | | | | Weighted Average Remaining Amortization Period | | Customer relationships | | 6.5 years | | Technology | | 2.6 years | | Trademarks and trade names | | 8.4 years | | | | | Total intangible assets | | 6.3 years |
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