Note 9. Goodwill and Other Intangible Assets

The changes in the carrying amount of goodwill are as follows:

(in thousands)	GES U.S.		GES International			Pursuit			Total
Balance at December 31, 2017	$	148,277	$	38,840		$	83,434		$	270,551
Foreign currency translation adjustments		—		(1,038	)		(3,490	)		(4,528	)
Balance at June 30, 2018	$	148,277	$	37,802		$	79,944		$	266,023

Other intangible assets consisted of the following:

	June 30, 2018							December 31, 2017
(in thousands)	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
Amortized intangible assets:
Customer contracts and relationships	$	68,454	$	(27,708	)	$	40,746	$	68,798	$	(23,696	)	$	45,102
Operating contracts and licenses		9,530		(1,207	)		8,323		9,951		(1,094	)		8,857
Tradenames		8,553		(3,343	)		5,210		8,633		(2,873	)		5,760
Non-compete agreements		5,298		(3,573	)		1,725		5,363		(3,007	)		2,356
Other		1,678		(745	)		933		896		(650	)		246
Total amortized intangible assets		93,513		(36,576	)		56,937		93,641		(31,320	)		62,321
Unamortized intangible assets:
Business licenses		460		—			460		460		—			460
Other intangible assets	$	93,973	$	(36,576	)	$	57,397	$	94,101	$	(31,320	)	$	62,781

Intangible asset amortization expense was $2.9 million for the three months ended June 30, 2018 and $5.5 million for the six months ended June 30, 2018. Intangible asset amortization expense was $3.3 million for the three months ended June 30, 2017 and $6.3 million for the six months ended June 30, 2017. The weighted-average amortization period of: customer contracts and relationships is approximately 8.1 years, operating contracts and licenses is approximately 25.9 years, tradenames is approximately 6.6 years, non-compete agreements is approximately 1.8 years, and other amortizable intangible assets is approximately 8.2 years. The estimated future amortization expense related to amortized intangible assets held at June 30, 2018 is as follows:

(in thousands)
Year ending December 31,
Remainder of 2018	$	5,527
2019		9,951
2020		8,455
2021		7,465
2022		5,932
Thereafter		19,607
Total	$	56,937