Goodwill and Other Intangible Assets

Changes in the carrying amount of goodwill for the six months ended January 31, 2019, were as follows:



	IDS			WPS			Total
Balance as of July 31, 2018	$	385,524		$	34,291		$	419,815
Translation adjustments	(2,178		)	(397		)	(2,575		)
Balance as of January 31, 2019	$	383,346		$	33,894		$	417,240

Goodwill is presented net of accumulated impairment losses, with the most recent impairment charge being incurred in fiscal 2015.

Other intangible assets include patents, trademarks, and customer relationships with finite lives being amortized in accordance with the accounting guidance for other intangible assets. The Company also has unamortized indefinite-lived trademarks that are classified as other intangible assets. The net book value of these assets was as follows:



	January 31, 2019								July 31, 2018
	Weighted Average Amortization Period (Years)	Gross Carrying Amount		Accumulated Amortization			Net Book Value		Weighted Average Amortization Period (Years)	Gross Carrying Amount		Accumulated Amortization			Net Book Value
Amortized other intangible assets:
Patents	5	$	1,448	$	(1,195	)	$	253	5	$	1,448	$	(942	)	$	506
Trademarks and other	10	2,467		(2,398		)	69		9	4,497		(4,395		)	102
Customer relationships	8	48,465		(28,607		)	19,858		9	55,999		(33,535		)	22,464
Unamortized other intangible assets:
Trademarks	N/A	19,472		—			19,472		N/A	19,516		—			19,516
Total		$	71,852	$	(32,200	)	$	39,652		$	81,460	$	(38,872	)	$	42,588

Amortization expense of intangible assets was $1,434 and $1,617 for the three months ended January 31, 2019 and 2018, respectively, and $2,870 and $3,310 for the six months ended January 31, 2019 and 2018, respectively. The amortization over each of the next five fiscal years is projected to be $5,717, $5,191, $5,151, $5,006 and $2,025 for the fiscal years ending July 31, 2019, 2020, 2021, 2022 and 2023, respectively.