GOODWILL AND OTHER INTANGIBLE ASSETS

The changes in goodwill by segment for the nine months ended September 30, 2018 were as follows (in thousands):



	Environmental Services			Safety-Kleen			Totals
Balance at January 1, 2018	$	172,386		$	306,137		$	478,523
Increase from current period acquisitions	33,281			4,168			37,449
Measurement period adjustments from prior period acquisitions	(78		)	—			(78		)
Foreign currency translation	(829		)	(963		)	(1,792		)
Balance at September 30, 2018	$	204,760		$	309,342		$	514,102

The Company assesses goodwill for impairment on an annual basis as of December 31, or at an interim date when events or changes in the business environment would more likely than not reduce the fair value of a reporting unit below its carrying value.

As discussed in Note 18, “Segment Reporting,” during the first quarter of fiscal year 2018 and as a result of operational and managerial changes in several of the Company’s businesses, the identification of operating segments in accordance with ASC 280, Segment Information, was changed. As a result of the Company's conclusions about the identification of operating segments, the Company also concluded that, for purposes of reviewing for potential goodwill impairment, it now has four reporting units, consisting of Environmental Sales and Service, Environmental Facilities, Kleen Performance Products and Safety-Kleen Environmental Services. The Company allocated goodwill to the newly identified reporting units using a relative fair value approach. In addition, the Company completed an assessment of any potential goodwill impairment for all reporting units immediately prior and subsequent to the reallocation and determined that no impairment existed.

As of September 30, 2018 and December 31, 2017, the Company's total finite-lived and indefinite-lived intangible assets consisted of the following (in thousands):



	September 30, 2018						December 31, 2017
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	177,628	$	78,419	$	99,209	$	174,721	$	74,347	$	100,374
Customer and supplier relationships	400,292		178,506		221,786		399,224		158,972		240,252
Other intangible assets	37,844		31,412		6,432		36,766		31,592		5,174
Total amortizable permits and other intangible assets	615,764		288,337		327,427		610,711		264,911		345,800
Indefinite lived trademarks and trade names	123,928		—		123,928		123,328		—		123,328
Total permits and other intangible assets	$	739,692	$	288,337	$	451,355	$	734,039	$	264,911	$	469,128

Amortization expense of permits and other intangible assets was $8.1 million and $26.0 million in the three and nine months ended September 30, 2018, respectively. Amortization expense of permits and other intangible assets was $8.9 million and $27.7 million in the three and nine months ended September 30, 2017, respectively.

The expected amortization of the net carrying amount of finite-lived intangible assets at September 30, 2018 was as follows (in thousands):



Years Ending December 31,	Expected Amortization
2018 (three months)	$	8,481
2019	32,488
2020	30,137
2021	27,645
2022	27,476
Thereafter	201,200
	$	327,427