We have two operating and reportable segments: (1) Software Products and (2) Professional Services. We assess goodwill for impairment at the reporting unit level. Our reporting units are determined based on the components of our operating segments that constitute a business for which discrete financial information is available and for which operating results are regularly reviewed by segment management. Our reporting units are the same as our operating segments.

As of March 31, 2022, goodwill and acquired intangible assets in the aggregate attributable to our Software Products segment was $2,496.7 million and attributable to our Professional Services segment was $44.8 million. As of September 30, 2021, goodwill and acquired intangible assets in the aggregate attributable to our Software Products segment was $2,525.7 million and attributable to our Professional Services segment was $45.2 million. Acquired intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. We evaluate goodwill for impairment in the third quarter of our fiscal year, or on an interim basis if an event occurs or circumstances change that would, more likely than not, reduce the fair value of a reporting segment below its carrying value. Factors we consider important, on an overall company basis and segment basis, when applicable, that could trigger an impairment review include significant under-performance relative to historical or projected future operating results, significant changes in our use of the acquired assets or the strategy for our overall business, significant negative industry or economic trends, a significant decline in our stock price for a sustained period and a reduction of our market capitalization relative to net book value.

We completed our annual goodwill impairment review as of June 30, 2021 based on a qualitative assessment. Our qualitative assessment included company-specific (e.g., financial performance and long-range plans), industry, and macroeconomic factors, as well as consideration of the fair value of each reporting unit relative to its carrying value at the last valuation date (June 27, 2020). Based on our qualitative assessment, we believe it is more likely than not that the fair values of our reporting units exceed their carrying values and no further impairment testing is required. Through March 31, 2022, there were no events or changes in circumstances that indicated that the carrying values of goodwill or acquired intangible assets may not be recoverable.

(in thousands)	March 31, 2022						September 30, 2021
	Gross Carrying Amount		Accumulated Amortization		Net Book Value		Gross Carrying Amount		Accumulated Amortization		Net Book Value
Goodwill (not amortized)					$	2,186,156					$	2,191,887
Intangible assets with finite lives (amortized):
Purchased software	$	487,399	$	348,736	$	138,663	$	483,771	$	338,542	$	145,229
Capitalized software		22,877		22,877		—		22,877		22,877		—
Customer lists and relationships		570,920		363,623		207,297		574,516		350,648		223,868
Trademarks and trade names		26,772		17,372		9,400		26,906		17,036		9,870
Other		3,933		3,933		—		4,000		4,000		—
Total intangible assets with finite lives	$	1,111,901	$	756,541	$	355,360	$	1,112,070	$	733,103	$	378,967
Total goodwill and acquired intangible assets					$	2,541,516					$	2,570,854

(in thousands)	Software Products			Professional Services			Total
Balance, October 1, 2021	$	2,148,968		$	42,919		$	2,191,887
Acquisitions		691			—			691
Foreign currency translation adjustment		(6,296	)		(126	)		(6,422	)
Balance, March 31, 2022	$	2,143,363		$	42,793		$	2,186,156

The aggregate amortization expense for intangible assets with finite lives is classified in our Consolidated Statements of Operations as follows:

(in thousands)	Three months ended				Six months ended
	March 31, 2022		March 31, 2021		March 31, 2022		March 31, 2021
Amortization of acquired intangible assets	$	8,450	$	7,650	$	16,934	$	14,197
Cost of license revenue		5,921		7,117		12,414		13,384
Total amortization expense	$	14,371	$	14,767	$	29,348	$	27,581