Note 6 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Years ended December 31,
	2023			2022		2021
Current:
Federal	$	146,595		$	85,855	$	142,542
State and local		44,328			51,078		43,004
		190,923			136,933		185,546
Deferred:
Federal		23,544			172,334		43,900
State and local		(7,867	)		2,755		9,520
		15,677			175,089		53,420
Total tax expense/(benefit)	$	206,600		$	312,022	$	238,966

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Years ended December 31,
	2023			2022			2021
Income tax at federal statutory rate	$	196,326		$	269,088		$	209,952
State tax, net of federal effect		28,997			41,624			37,223
Benefit of stock compensation		(7,442	)		(7,584	)		(7,583	)
199/R&D credit, net of FIN 48		(622	)		5,839			(1,524	)
Federal 1341 Claim		(14,616	)		-			-
Nondeductible meals and entertainment		2,331			294			130
Change in effective state tax rate, net of federal benefit		(193	)		1,561			(724	)
Other, net		1,819			1,200			1,492
Total tax expense	$	206,600		$	312,022		$	238,966

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,
	2023			2022
Deferred tax assets:
Insurance accruals	$	104,720		$	54,047
Allowance for doubtful accounts		10,766			10,230
Compensation accrual		8,003			30,492
Deferred compensation accrual		36,309			28,249
Federal benefit of state uncertain tax positions		17,491			16,280
Lease liabilities		82,048			71,732
State NOL carry-forward		5,478			6,765
Other		7,673			7,361
Total gross deferred tax assets		272,488			225,156
Valuation allowance		(5,478	)		(6,765	)
Total deferred tax assets, net of valuation allowance		267,010			218,391
Deferred tax liabilities:
Plant and equipment, principally due to differences in depreciation		1,057,922			1,011,963
Prepaid permits and insurance, principally due to expensing for income tax purposes		63,880			55,132
Lease right-of-use assets		81,416			71,827
Total gross deferred tax liabilities		1,203,218			1,138,922
Net deferred tax liability	$	936,208		$	920,531

Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Table Text Block]

	December 31,
	2023			2022			2021
Beginning balance	$	89.1		$	78.5		$	66.1
Additions based on tax positions related to the current year		16.2			25.8			14.9
Additions/(reductions) based on tax positions taken in prior years		0.5			2.8			4.8
Reductions due to settlements		(14.6	)		(8.0	)		(0.9	)
Reductions due to lapse of applicable statute of limitations		(10.3	)		(10.0	)		(6.4	)
Ending balance	$	80.9		$	89.1		$	78.5