Fair Value Measurement - Recurring and Nonrecurring Measurements (Details) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[1]	$ 40,859			$ 40,859
Asset Impairment Charges		(3,982)		$ 0
Gain (Loss) on Disposition of Property Plant Equipment		6,651		20,879
Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment		6,700		20,900
U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[1]	134,107			134,107
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure		0			0
Business Combination, Contingent Consideration, Liability	[2]	40,859			40,859
Contingent Consideration Gain (Loss)		0	[2]	$ 0	(3,359)	[2]
Total pension plan assets		34,412			35,423
Fair Value, Recurring [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		134,107			134,107	[2]
Contingent Consideration Gain (Loss)		0			0	[2]
Fair Value, Recurring [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		33,341			34,536
Fair Value, Recurring [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		1,071			887
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[2]	0			0
Total pension plan assets		34,412			35,423
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		0			0	[2]
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		33,341			34,536
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		1,071			887
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[2]	0			0
Total pension plan assets		0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		0			0	[2]
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[2]	40,859			40,859
Total pension plan assets		0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		134,107			134,107	[2]
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		0			0
Fair Value, Nonrecurring [Member] | Software and Software Development Costs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[3]				0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member] | Software and Software Development Costs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[3]				0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member] | Software and Software Development Costs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[3]				0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Software and Software Development Costs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[3]				0
Building and Building Improvements | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[4]	0			0
Asset Impairment Charges	[4]	(288)			(187)
Building and Building Improvements | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[4]	0			0
Building and Building Improvements | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[4]	0			0
Building and Building Improvements | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[4]	0			0
Equipment [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[5]	0			0
Total Losses, nonrecurring assets	[5]	(3,694)			(469)
Equipment [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[5]	0			0
Equipment [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[5]	0			0
Equipment [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[5]	$ 0			0
Software and Software Development Costs | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Impairment Charges	[3]				$ (1,580)

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

[2] Contingent consideration is associated with the U.S. Xpress Acquisition and certain other investments. The Company did not recognize any gains (losses) in the quarters ended March 31, 2024 and 2023 related to the revaluation of these liabilities.

[3] Reflects the non-cash impairment of software (within the All Other Segments).

[4] Reflects the non-cash impairment of building improvements (within the Truckload segment and the All Other Segments).

[5] Reflects the non-cash impairment of certain revenue equipment held for sale (within the Truckload segment and the All Other Segments).