Goodwill and Intangible Assets

Identifiable intangible assets that are separable and have determinable useful lives are valued separately and amortized over their benefit period. The following is the gross carrying value and accumulated amortization of the Company’s identifiable intangible assets as of December 31, 2019 and December 31, 2018 (in thousands):



	December 31, 2019							December 31, 2018
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Tradenames	$	15,980	$	(13,563	)	$	2,417	$	15,980	$	(10,423	)	$	5,557
Customer relationships	267,781		(156,337		)	111,444		250,498		(112,757		)	137,741
Other intangible assets	—		—			—		3,489		(911		)	2,578
	$	283,761	$	(169,900	)	$	113,861	$	269,967	$	(124,091	)	$	145,876

The weighted average amortization period of these intangible assets in the aggregate is 3.9 years. Total amortization expense of intangible assets above was $46.7 million and $44.0 million for the years ended December 31, 2019 and 2018, respectively.

Future amortization for the next five years and thereafter is as follows (in thousands):



Years Ending December 31,
2020	$	46,528
2021	28,886
2022	13,623
2023	7,271
2024	6,534
Thereafter	11,019
	$	113,861

Changes in goodwill between December 31, 2018 and December 31, 2019 consisted of the following (in thousands):



	Carrying Value
Balance at December 31, 2018	$	484,941
Goodwill acquired	9,403
Purchase price allocation adjustments from prior periods	2
Impact of foreign currency exchange rates	1,378
Balance at December 31, 2019	$	495,724

Changes to initial purchase price allocations related to acquisitions may arise from changes in estimates from conditions that existed at the applicable acquisition date and as a result of net working capital adjustments. The Company performed its goodwill impairment test as of October 1, 2019, and the fair value substantially exceeded the carrying value, as such, there was no impairment related to goodwill.