Goodwill represents the excess of the purchase price of acquisitions over the fair value of the identifiable net assets acquired. Our goodwill balance as of September 30, 2024 and December 31, 2023 was $331.7 million and was comprised of $317.5 million and $14.2 million in our Truckload and Logistics segments, respectively. As of September 30, 2024 and December 31, 2023, our Truckload segment had accumulated goodwill impairment charges of $34.6 million.

The identifiable finite lived intangible assets listed below are included in internal use software and other noncurrent assets on the consolidated balance sheets and relate to the acquisitions of MLS and M&M.


	September 30, 2024						December 31, 2023
(in millions)	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Customer relationships	$	43.5	$	4.0	$	39.5	$	43.5	$	1.8	$	41.7
Trademarks	10.9		2.2		8.7		10.9		1.5		9.4
Non-compete agreements	5.4		1.3		4.1		5.4		0.4		5.0
Total intangible assets	$	59.8	$	7.5	$	52.3	$	59.8	$	3.7	$	56.1

Amortization expense for intangible assets was $1.2 million and $0.9 million for the three months ended September 30, 2024 and 2023, respectively, and $3.8 million and $1.4 million for the nine months ended September 30, 2024 and 2023, respectively.

Estimated future amortization expense related to intangible assets is as follows:


(in millions)	September 30, 2024
Remaining 2024	$	1.2
2025	5.0
2026	5.0
2027	5.0
2028	4.6
2029 and thereafter	31.5
Total	$	52.3