GOODWILL AND OTHER INTANGIBLE ASSETS

The changes in goodwill for the years ended December 31, 2018 and 2017 were as follows (in thousands):



	Environmental Services			Safety-Kleen			Totals
Balance at January 1, 2017	$	169,084		$	296,070		$	465,154
Increase from current period acquisitions	3,000			5,687			8,687
Measurement period adjustments from prior period acquisitions	—			2,186			2,186
Decrease from disposition of business	(1,300		)	—			(1,300		)
Foreign currency translation	1,602			2,194			3,796
Balance at December 31, 2017	$	172,386		$	306,137		$	478,523
Increase from current period acquisitions	37,007			3,697			40,704
Measurement period adjustments from prior period acquisitions	(78		)	—			(78		)
Foreign currency translation	(2,296		)	(2,664		)	(4,960		)
Balance at December 31, 2018	$	207,019		$	307,170		$	514,189

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.

The Company conducted its annual impairment test of goodwill as of December 31, 2018 and determined that no adjustment to the carrying value of goodwill for any reporting unit was then necessary because the fair values of the reporting units exceeded their respective carrying values. The fair value of all reporting units was determined using an income approach based upon estimates of future discounted cash flows. The resulting estimates of fair value were validated through the consideration of other factors such as the fair value of comparable companies to the reporting units and a reconciliation of the sum of all estimated fair values of the reporting units to the Company’s overall market capitalization. In all cases, the estimated fair values of the reporting units significantly exceeded their carrying values.

(8) GOODWILL AND OTHER INTANGIBLE ASSETS (Continued)

Significant judgments and unobservable inputs categorized as Level 3 in the fair value hierarchy are inherent in the impairment tests performed and include assumptions about the amount and timing of expected future cash flows, growth rates, and the determination of appropriate discount rates. Level 3 inputs are unobservable inputs for the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. The Company believes that the assumptions used in its annual and any interim date impairment tests are reasonable, but variations in any of the assumptions may result in different calculations of fair values.

The impacts of any adverse business and market conditions which impact the overall performance of the Company's reporting units will continue to be monitored. If the Company's reporting units do not achieve the financial performance that the Company expects, it is possible that goodwill impairment charges may result. There can therefore be no assurance that future events will not result in an impairment of goodwill.

At December 31, 2018, the total of accumulated goodwill impairment charges was $189.4 million, of which $34.0 million was recorded during the year ended December 31, 2016 within the Environmental Services reporting unit, due to economic conditions in Western Canada's Oil Sands region and the impacts on the Company's lodging operations.

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



	December 31, 2018						December 31, 2017
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	177,583	$	79,358	$	98,225	$	174,721	$	74,347	$	100,374
Customer and supplier relationships	393,487		179,824		213,663		399,224		158,972		240,252
Other intangible assets	37,262		29,743		7,519		36,766		31,592		5,174
Total amortizable permits and other intangible assets	608,332		288,925		319,407		610,711		264,911		345,800
Trademarks and trade names	122,468		—		122,468		123,328		—		123,328
Total permits and other intangible assets	$	730,800	$	288,925	$	441,875	$	734,039	$	264,911	$	469,128

The Company regularly monitors and assesses whether events or changes in circumstances relative to the Company's business might indicate that future cash flows attributable to the Company's asset groups may not be sufficient to recover the current value of those assets. During the year ended and as of December 31, 2018, there were no events or changes in circumstances which would indicate that the carrying values of the Company's asset groups would not be recoverable and thus no impairment charge was recorded related to the Company's long-lived assets. If expectations of future cash flows were to decrease in the future as a result of worse than expected or prolonged periods of depressed activity, future impairments may become evident.

Amortization expense of permits and other intangible assets for the years ended December 31, 2018, 2017 and 2016 were $34.4 million, $37.0 million and $40.0 million, respectively.

The expected amortization of the net carrying amount of finite-lived intangible assets at December 31, 2018 is as follows (in thousands):



Years Ending December 31,	Expected Amortization
2019	$	33,091
2020	30,195
2021	27,553
2022	27,386
2023	23,468
Thereafter	177,714
	$	319,407