8. GOODWILL AND OTHER INTANGIBLE ASSETS

In accordance with the Company’s goodwill policy as stated in Note 2, Summary of Significant Accounting Policies, the Company has evaluated the goodwill for impairment indicators and as of December 31, 2021, the Company has not recognized any impairments of the acquired goodwill.

(1) The increase in customer relationships for the year ended December 31, 2021 is due to the Company acquiring $68.8 million of related intangibles from the Crouse and Keystone acquisitions. The acquired customer relationships have a weighted average amortization period of 12 years.

(2) The increase in trade names for the year ended December 31, 2021 is due to the Company acquiring $1.3 million of related intangibles from the Crouse and Keystone acquisitions. The acquired trade names have a weighted average amortization period of 3 years.

(3) The Company previously excluded intangible assets that were fully amortized from the cost and accumulated amortization presentation. As of December 31, 2021, the Company includes the total gross value of all purchased intangibles, including assets that were fully amortized.

The value of internally developed software in development not yet placed in service were $7.1 million and $5.8 million as of December 31, 2021 and 2020, respectively. As of December 31, 2021, the Company has not written off any costs associated with internally developed software in development not yet placed in service.

The aggregate amortization expense from finite-lived intangible assets was $107.7 million and $63.6 million for the years ended December 31, 2021 and 2020, respectively. The estimated future amortization for finite-lived intangible assets as of December 31, 2021, is as follows: