5. Goodwill and Other Intangible Assets

The changes in the carrying amount of goodwill for the nine months ended September 30, 2018 were as follows:

	Business Services			Marketing Solutions			Total
Net book value as of December 31, 2017
Goodwill	$	2,759.8		$	519.5		$	3,279.3
Accumulated impairment losses		(2,436.7	)		(254.1	)		(2,690.8	)
Total		323.1			265.4			588.5
Disposition		(32.4	)		—			(32.4	)
Foreign exchange		(1.8	)		—			(1.8	)

Net book value as of September 30, 2018
Goodwill		2,631.7			519.5			3,151.2
Accumulated impairment losses		(2,342.8	)		(254.1	)		(2,596.9	)
Total	$	288.9		$	265.4		$	554.3

During the three months ended September 30, 2018 we reduced goodwill by $32.4 million for the disposition of our Print Logistics business. See Note 16, Disposition, for further discussion.

The components of other intangible assets at September 30, 2018 and December 31, 2017 were as follows:

	September 30, 2018							December 31, 2017
	Gross							Gross
	Carrying		Accumulated			Net Book		Carrying		Accumulated			Net Book
	Amount		Amortization			Value		Amount		Amortization			Value

Client relationships	$	524.2	$	(423.2	)	$	101.0	$	534.1	$	(412.4	)	$	121.7
Patents		2.0		(2.0	)		—		2.0		(2.0	)		—
Trademarks, licenses and agreements		25.7		(25.1	)		0.6		26.2		(25.2	)		1.0
Trade names		34.7		(16.1	)		18.6		36.8		(16.2	)		20.6
Total other intangible assets	$	586.6	$	(466.4	)	$	120.2	$	599.1	$	(455.8	)	$	143.3

Amortization expense for other intangible assets was $6.8 million and $20.7 million for the three and nine months ended September 30, 2018, respectively. Amortization expense for other intangible assets was $7.1 million and $21.6 million for the three and nine months ended September 30, 2017, respectively.