Fair Value Measurement - Estimated Fair Values (Details) - USD ($) $ in Thousands		Jun. 30, 2024	Dec. 31, 2023
Financial Assets:
Equity method investments		$ 120,161	$ 102,252
Equity method investments (Estimated Fair Value)		120,161	102,252
Financial Liabilities:
Term loan Carrying Value		1,643,946	1,628,079
Revolving line of credit		120,000	67,000
Accounts receivable securitization		452,039	526,508
Business Combination, Contingent Consideration, Liability	[1]	40,859	40,859
U.S. Xpress | Class A
Financial Liabilities:
Business Combination, Contingent Consideration, Liability	[1]	134,107	134,107
2021 Term Loan A-2
Financial Liabilities:
Term loan Carrying Value	[2]	199,975	199,902
Term loan, Fair Value	[2]	200,000	200,000
2021 Term Loan A-3
Financial Liabilities:
Term loan Carrying Value	[2]	799,235	799,058
Term loan, Fair Value	[2]	800,000	800,000
2023 Term Loan
Financial Liabilities:
Term loan Carrying Value	[3]	249,297	249,135
Term loan, Fair Value	[3]	250,000	250,000
2021 Revolver
Financial Liabilities:
Revolving line of credit		120,000	67,000
U.S. Xpress Revenue Equipment Installment Notes
Financial Liabilities:
Secured Debt	[4]	251,335	279,339
Debt Instrument, Fair Value Disclosure		900	1,300
2021 Prudential Notes
Financial Liabilities:
Term loan Carrying Value	[5]	16,909	25,078
Term loan, Fair Value	[5]	16,925	25,100
Debt Instrument, Fair Value Disclosure		900	1,100
Deferred loan costs		16	22
2023 RSA
Financial Liabilities:
Accounts receivable securitization	[6]	452,039	526,508
Debt Instrument, Fair Value Disclosure	[6]	452,400	527,000
Deferred loan costs		$ 400	$ 500

[1] The contingent consideration is primarily related to the U.S. Xpress Acquisition.

[2] As of June 30, 2024, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $25,000 and $0.8 million in deferred loan costs, respectively. As of December 31, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $0.9 million in deferred loan costs, respectively.

[3] As of June 30, 2024, the carrying amount of the 2023 Term Loan was net of $0.7 million in deferred loan costs. As of December 31, 2023, the carrying amount of the 2023 Term Loan was net of $0.9 million in deferred loan costs.

[4] As of June 30, 2024, the carrying amount of the revenue equipment installment notes included $0.9 million in fair value adjustments. As of December 31, 2023, the carrying amount of the revenue equipment installment notes included $1.3 million in fair value adjustments.

[5] As of June 30, 2024, the carrying amount of the 2021 Prudential Notes was net of approximately $16,000 in deferred loan costs and included $0.9 million in fair value adjustments. As of December 31, 2023, the carrying amount of the 2021 Prudential Notes was net of $22,000 in deferred loan costs and included $1.1 million in fair value adjustments.

[6] The carrying amount of the 2023 RSA was net of $0.4 million and $0.5 million in deferred loan costs as of June 30, 2024 and December 31, 2023, respectively.