The following table presents the changes in the carrying amount of goodwill by reportable segment:

	Commercial			Government
($ in thousands)	Services			Solutions		Total
Balance at December 31, 2019	$	424,404		$	159,746	$	584,150
Foreign currency translation adjustment		(2,535	)		—		(2,535	)
Balance at June 30, 2020	$	421,869		$	159,746	$	581,615

	June 30, 2020						December 31, 2019
	Weighted						Weighted
	Average	Gross					Average	Gross
	Remaining	Carrying			Accumulated		Remaining	Carrying			Accumulated
($ in thousands)	Useful Life	Amount			Amortization		Useful Life	Amount			Amortization
Trademarks	0.9 years	$	32,067		$	24,209	1.5 years	$	32,127		$	19,106
Non-compete agreements	2.5 years		62,555			31,119	3.0 years		62,549			24,834
Customer relationships	6.4 years		365,368			103,204	6.9 years		366,533			82,903
Developed technology	2.8 years		165,520			80,615	3.3 years		165,708			65,631
Gross carrying value of intangible assets			625,510		$	239,147			626,917		$	192,474
Less: accumulated amortization			(239,147	)					(192,474	)
Intangible assets, net		$	386,363					$	434,443

Amortization expense was $23.5 million and $23.1 million for the three months ended June 30, 2020 and 2019, respectively, and was $47.1 million and $46.3 million for the six months ended June 30, 2020 and 2019, respectively.

During the fourth quarter of each fiscal year, we perform our annual goodwill impairment test for each of our reporting units. Our reporting units are the same as our two reportable segments (Government Solutions and Commercial Services). We also test goodwill for impairment whenever events or circumstances occur which, in our judgment, could more likely than not reduce the fair value of one or more reporting units below its carrying amount. Potential impairment indicators include, but are not limited to, (i) a deterioration of the business environments in which we operate; (ii) downward revisions to internal forecasts, and the magnitude thereof, if any; and (iii) declines in our market capitalization below our book value, and the magnitude and duration of those declines, if any.

During the first half of fiscal 2020, our market capitalization declined significantly compared to December 31, 2019. Over the same period, the equity value of our key Commercial Services customers, our peer group companies and the overall U.S. stock market also declined significantly amid market volatility. These declines were driven by the uncertainty surrounding the outbreak of the novel coronavirus (“COVID-19”) and other macroeconomic events. Based on these factors, we concluded that a triggering event occurred and, accordingly, an interim quantitative impairment test was performed as of March 31, 2020 and updated as of June 30, 2020.

Based upon the results of our interim impairment tests, we concluded that the fair values of the Government Solutions and Commercial Services reporting units exceeded their carrying value. The current economic conditions due to COVID-19 are still evolving and any significant adverse changes in future periods to our internal forecasts or the external market conditions, if any, could reasonably be expected to negatively affect our key assumptions and may result in a future goodwill impairment charge, which could be material.