Fair Value Measurement - Recurring and Nonrecurring Measurements (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended			12 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024		Jun. 30, 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			$ 40,859
Asset Impairment Charges		(5,877)	$ 0	(9,859)		$ 0
Gain (Loss) on Disposition of Property Plant Equipment				12,604		35,180
Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment		6,000	14,300	12,600		35,200
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			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			0
Business Combination, Contingent Consideration, Liability	[2]	40,859		40,859			40,859
Contingent Consideration Gain (Loss)		0	$ (2,500)	0	[2]	$ (2,500)	(3,359)	[2]
Total pension plan assets		33,783		33,783			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	[2]	134,107		134,107			134,107
Contingent Consideration Gain (Loss)	[2]			0			0
Fair Value, Recurring [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		32,800		32,800			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		983		983			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			0
Total pension plan assets		33,783		33,783			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	[2]	0		0			0
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		32,800		32,800			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		983		983			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			0
Total pension plan assets		0		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	[2]	0		0			0
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			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			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			40,859
Total pension plan assets		0		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	[2]	134,107		134,107			134,107
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			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			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			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			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			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			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			0
Property Subject to Operating Lease | 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
Asset Impairment Charges	[5]			(5,300)
Property Subject to Operating Lease | 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
Property Subject to Operating Lease | 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
Property Subject to Operating Lease | 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
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	[6]	0		0			0
Total Losses, nonrecurring assets	[6]			(4,271)			(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	[6]	0		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	[6]	0		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	[6]	$ 0		$ 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] The 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 quarter and year-to-date periods ended June 30, 2024.The Company recognized a gain of $2.5 million during the quarter and year-to-date periods ended June 30, 2023.

[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 related to the market value of a facility lease (within the Truckload Segment).

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