Goodwill and Other Intangible Assets

A summary of changes in the Company’s goodwill by reportable business segment is as follows (in thousands):



	December 31, 2017		Acquisition Accounting Adjustments		Foreign Currency			September 30, 2018
Segment
North America	$	3,084,123	$	4,036	$	(7,152	)	$	3,081,007
International	1,631,700		20		(195,379		)	1,436,341
	$	4,715,823	$	4,056	$	(202,531	)	$	4,517,348

As of September 30, 2018 and December 31, 2017, other intangible assets consisted of the following (in thousands):



		September 30, 2018							December 31, 2017
	Weighted- Avg Useful Lives (Years)	Gross Carrying Amounts		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amounts		Accumulated Amortization			Net Carrying Amount
Customer and vendor relationships	17.1	$	2,609,056	$	(734,726	)	$	1,874,330	$	2,698,428	$	(605,347	)	$	2,093,081
Trade names and trademarks—indefinite lived	N/A	476,820		—			476,820		499,587		—			499,587
Trade names and trademarks—other	13.8	2,963		(2,457		)	506		2,986		(2,207		)	779
Software	5.9	212,288		(144,880		)	67,408		219,019		(116,654		)	102,365
Non-compete agreements	4.2	45,786		(26,223		)	19,563		48,221		(19,076		)	29,145
Total other intangibles		$	3,346,913	$	(908,286	)	$	2,438,627	$	3,468,241	$	(743,284	)	$	2,724,957

Changes in foreign exchange rates resulted in a $125.2 million decrease to the carrying values of other intangible assets in the nine months ended September 30, 2018. Amortization expense related to intangible assets for the nine months ended September 30, 2018 and 2017 was $165.0 million and $158.9 million, respectively.