Intangibles

The company's intangibles consist of the following (in thousands):


	December 31, 2021				December 31, 2020
	Historical Cost		Accumulated Amortization		Historical Cost		Accumulated Amortization
Customer lists	$	52,447	$	52,447	$	54,502	$	54,502
Trademarks	24,137		—		25,112		—
Developed technology	7,652		7,149		7,924		7,204
Patents	5,543		5,543		5,556		5,556
License agreements	2,905		1,196		2,899		979
Other	1,147		1,140		1,162		1,151
Intangibles	$	93,831	$	67,475	$	97,155	$	69,392

All of the company's intangible assets have been assigned definite lives and continue to be amortized over their useful lives, except for trademarks shown above, which have indefinite lives.

The changes in intangible asset balances reflected on the balance sheet from December 31, 2020 to December 31, 2021 were the result of foreign currency translation on historical cost and accumulated amortization.

The company evaluates the carrying value of definite-lived assets annually in the fourth quarter and whenever events or circumstances indicate possible impairment. For the fourth quarter of 2021, the company concluded there was no impairment to be recorded.

Definite-lived assets are determined to be impaired if the future undiscounted cash flows expected to be generated by the asset are less than the carrying value. Actual impairment amounts for definite-lived assets are then calculated using a discounted cash flow calculation.

Any impairment for indefinite-lived intangible assets is calculated as the difference between the future discounted cash flows expected to be generated by the asset less than the carrying value for the asset. The company evaluated indefinite-lived intangible assets in the fourth quarter of 2021 and concluded there was no impairment to be recorded.

In 2019, the company recognized an intangible asset impairment charge in the Institutional Products Group reporting unit, which is part of the North America segment, of $587,000 ($435,000 after-tax) related to a trademark with an indefinite life. The fair value of the trademark was calculated using a relief from royalty payment methodology which requires applying an estimated market royalty rate to forecasted net sales and discounting the resulting cash flows to determine fair value. The fair values of the company's intangible assets were calculated using inputs that are not observable in the market and included

management's own estimates regarding the assumptions that market participants would use and thus these inputs are deemed Level III inputs in regard to the fair value hierarchy.

Amortization expense related to intangible assets was $404,000, $377,000 and $1,827,000 for 2021, 2020 and 2019, respectively. Amortization expense for 2019 includes impairments. Estimated amortization expense for each of the next five years is expected to be $398,000 for 2022, $398,000 in 2023, $348,000 in 2024, $213,000 in 2025 and $211,000 in 2026. Amortized intangible assets are being amortized on a straight-line basis over remaining lives of 3 to 8 years with a weighted average remaining life of approximately 6.8 years.