GOODWILL AND OTHER INTANGIBLE ASSETS

The following table summarizes the changes in the carrying amount of goodwill by segment for the nine month period ended July 31, 2018:



(in millions)	Rigid Industrial Packaging & Services		Paper Packaging & Services		Total
Balance at October 31, 2017	$	725.9	$	59.5	$	785.4
Currency translation	0.1		—		0.1
Balance at July 31, 2018	$	726.0	$	59.5	$	785.5

The following table summarizes the carrying amount of net other intangible assets by class as of July 31, 2018 and October 31, 2017:



(in millions)	Gross Intangible Assets		Accumulated Amortization		Net Intangible Assets
July 31, 2018:
Indefinite lived:
Trademarks and patents	$	13.4	$	—	$	13.4
Definite lived:
Customer relationships	$	164.0	$	104.0	$	60.0
Trademarks and patents	11.1		5.1		6.0
Other	21.9		16.0		5.9
Total	$	210.4	$	125.1	$	85.3

October 31, 2017:
Indefinite lived:
Trademarks and patents	$	13.4	$	—	$	13.4
Definite lived:
Customer relationships	$	170.2	$	99.7	$	70.5
Trademarks and patents	11.6		4.9		6.7
Other	23.4		16.0		7.4
Total	$	218.6	$	120.6	$	98.0

Amortization expense for the three months ended July 31, 2018 and 2017 was $3.8 million and $3.1 million, respectively. Amortization expense for the nine months ended July 31, 2018 and 2017 was $11.5 million and $10.0 million, respectively. Amortization expense for the next five years is expected to be $15.4 million in 2018, $15.1 million in 2019, $14.5 million in 2020, $12.9 million in 2021 and $8.9 million in 2022.

Definite lived intangible assets for the periods presented are subject to amortization and are being amortized using the straight-line method over periods that are contractually, legally determined, or over the period a market participant would benefit from the asset.