Intangible Assets

Intangible assets with finite lives are as follows:



	As of October 31, 2019
	Weighted Average Amortization Period	Gross Carrying Amount		Accumulated Amortization	Net Carrying Amount
Customer relationships	20.5	$	276,834,000	69,694,000	$	207,140,000
Technologies	12.7	92,649,000		60,948,000	31,701,000
Trademarks and other	16.7	31,026,000		13,183,000	17,843,000
Total		$	400,509,000	143,825,000	$	256,684,000



	As of July 31, 2019
	Weighted Average Amortization Period	Gross Carrying Amount		Accumulated Amortization	Net Carrying Amount
Customer relationships	20.5	$	276,834,000	66,484,000	$	210,350,000
Technologies	12.7	92,649,000		59,522,000	33,127,000
Trademarks and other	16.7	31,026,000		12,613,000	18,413,000
Total		$	400,509,000	138,619,000	$	261,890,000

The weighted average amortization period in the above table excludes fully amortized intangible assets.

Amortization expense for the three months ended October 31, 2019 and 2018 was $5,206,000 and $4,289,000, respectively.

The estimated amortization expense consists of the following for the fiscal years ending July 31:



2020	$	20,700,000
2021	19,563,000
2022	18,322,000
2023	18,322,000
2024	17,631,000

We review net intangible assets with finite lives for impairment when an event occurs indicating the potential for impairment. No such event has occurred during the three months ended October 31, 2019. We believe that the carrying values of our net intangible assets were recoverable as of October 31, 2019. Any impairment charges that we may record in the future could be material to our results of operations and financial condition.