Intangible Assets and Goodwill

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets and Goodwill

Intangible Assets and Goodwill

All intangible assets determined to have finite lives are amortized over their estimated useful lives. The useful life of an intangible asset is the period over which the asset is expected to contribute directly or indirectly to future cash flows. There was a $15.3 million change in the gross amount of identifiable intangible assets during the twelve months ended December 31, 2019, related to the acquisition of Millis Transfer. Amortization expense of $2.7 million, $2.5 million and $2.9 million for the twelve months ended December 31, 2019, 2018 and 2017, respectively, was included in depreciation and amortization in the consolidated statements of comprehensive income. Intangible assets subject to amortization consisted of the following at December 31, 2019 and 2018:

	2019
	Amortization period (years)	Gross Amount		Accumulated Amortization		Net intangible assets
		(in thousands)
Customer relationships	15-20	$	23,000	$	3,221	$	19,779
Tradename	0.5-10	12,900		8,260		4,640
Covenants not to compete	1-10	5,300		2,583		2,717
		$	41,200	$	14,064	$	27,136

	2018
	Amortization period (years)	Gross Amount		Accumulated Amortization		Net intangible assets
		(in thousands)
Customer relationships	20	$	13,600	$	2,329	$	11,271
Tradename	0.5-6	8,100		7,021		1,079
Covenants not to compete	1-10	4,200		2,056		2,144
		$	25,900	$	11,406	$	14,494

Future amortization expense for intangible assets is estimated at $2.4 million for 2020, $2.4 million for 2021, $2.3 million for 2022, $2.2 million for 2023, and $1.9 million for 2024.

Changes in carrying amount of goodwill during the twelve months ended December 31, 2019 and December 31, 2018 were as follows:

	(in thousands)
Balance at December 31, 2017	$	132,410
Acquisition	—
Balance at December 31, 2018	$	132,410
Acquisition	35,885
Balance at December 31, 2019	$	168,295