Intangible Assets |
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Goodwill and Intangible Assets Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Goodwill and Intangible Assets | (3) Intangible Assets Intangible assets associated with customer relationships are amortized on a straight-line basis over the expected period of benefits of the customer relationships, which ranged from 10 to 20 years at the time the intangible assets were originally recorded. The following table represents our change in carrying value of intangible assets (in millions):
The weighted average amortization period for intangible assets is 14.9 years. Amortization expense was $31.6 million and $30.9 million for the three months ended June 30, 2021 and 2020, respectively, and $62.5 million and $61.8 million for the six months ended June 30, 2021 and 2020, respectively. The following table summarizes our estimated aggregate amortization expense for the next five years and thereafter (in millions):
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