Description of Business and Summary of Accounting Policies - Schedule of Measure of Segment Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue		$ 3,209,074	$ 2,881,433	$ 2,792,057
Wages	[1]	907,750	767,282	689,342
Salaries	[1]	190,393	168,794	149,837
Purchased Transportation		237,306	238,688	315,896
Other Segment items	[2]	1,179,631	1,065,270	1,009,337
Depreciation and amortization		210,105	178,845	157,203
Interest Expense		8,930	2,535	2,611
Interest Income		(1,049)	(6,208)	(217)
Income Tax Expense		113,943	111,370	110,626
Segment and Consolidated Net Income		$ 362,065	$ 354,857	$ 357,422

[1] Wages includes payroll costs for non-management employees generally paid on an hourly or per-mile basis. Salaries includes payroll costs for exempt employees.

[2] Other segment items include employees' benefits, fuel, operating expenses and supplies, operating taxes and licenses and claims and insurance.