Our intangible assets are comprised of both indefinite-lived and finite-lived intangible assets. Intangible assets with indefinite lives and goodwill are not amortized; rather, they are reviewed for impairment at least annually or whenever events or circumstances indicate the carrying value of the asset may not be recoverable. We perform our annual impairment tests of our indefinite-lived intangible assets and goodwill during the fourth quarter of each fiscal year. We also reevaluate the useful life of indefinite-lived intangible assets each reporting period to determine whether events and circumstances continue to support an indefinite useful life. The results of our annual indefinite-lived intangible assets and goodwill impairment assessments in the fourth quarter of 2019 indicated no impairment. As of September 30, 2020, as a result of COVID-19, we reviewed the carrying value of our indefinite-lived intangible assets and goodwill and concluded there were no impairments.

As of both September 30, 2020 and December 31, 2019, our goodwill balance was $0.6 million.

Our intangible assets, other than goodwill, as of September 30, 2020 and December 31, 2019 were as follows (in thousands, except for weighted average remaining useful life):

	Weighted
	Average			As of September 30, 2020										As of December 31, 2019
	Remaining			Gross							Net				Gross							Net
	Useful Life			Carrying			Accumulated				Carrying				Carrying			Accumulated				Carrying
	(in years)			Amount			Amortization				Amount				Amount			Amortization				Amount
Amortized intangible assets:

Software		3.4	$		48,572	$		(29,787)		$		18,785	$			42,591	$		(25,191)		$		17,400
Other intangible assets		8.0			1,500			-				1,500				1,500			-				1,500
Service customer relationships					8,081			(8,081	)			-				8,081			(8,081	)			-
OEM and dealer relationships					6,724			(6,724	)			-				6,724			(6,724	)			-
Total amortized intangible assets					64,877			(44,592)				20,285				58,896			(39,996)				18,900

Unamortized intangible assets:

FCC Licenses					32,283			-				32,283				32,283			-				32,283

Total intangible assets			$		97,160	$		(44,592)		$		52,568	$			91,179	$		(39,996	)	$		51,183

Amortization expense was $1.6 million and $4.6 million, respectively, for the three and nine month periods ended September 30, 2020 and $1.2 million and $4.2 million, respectively, for the prior-year periods.

Amortization expense for each of the next five years and thereafter is estimated to be as follows (in thousands):

Actual future amortization expense could differ from the estimated amount as a result of future investments and other factors.