Note 6 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

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

	Years ended December 31,
	2022		2021		2020
Current:
Federal	$	85,855	$	142,542	$	138,952
State and local		51,078		43,004		28,094
		136,933		185,546		167,046
Deferred:
Federal		172,334		43,900		(2,392	)
State and local		2,755		9,520		(4,664	)
		175,089		53,420		(7,056	)
Total tax expense/(benefit)	$	312,022	$	238,966	$	159,990

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

	Years ended December 31,
	2022			2021			2020
Income tax at federal statutory rate	$	269,088		$	209,952		$	139,865
State tax, net of federal effect		41,624			37,223			20,071
Benefit of stock compensation		(7,584	)		(7,583	)		(3,503	)
199/R&D credit		5,839			(1,524	)		-
Nondeductible meals and entertainment		294			130			1,344
Change in effective state tax rate, net of federal benefit		1,561			(724	)		98
Other, net		1,200			1,492			2,115
Total tax expense	$	312,022		$	238,966		$	159,990

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

	December 31,
	2022			2021
Deferred tax assets:
Insurance accruals	$	54,047		$	27,487
Allowance for doubtful accounts		10,230			8,886
Compensation accrual		30,492			22,061
CARES Act payroll tax deferral		-			9,955
Deferred compensation accrual		28,249			28,937
Federal benefit of state uncertain tax positions		16,280			12,870
Lease liabilities		71,732			43,850
State NOL carry-forward		6,765			7,303
Other		7,361			5,549
Total gross deferred tax assets		225,156			166,898
Valuation allowance		(6,765	)		(7,303	)
Total deferred tax assets, net of valuation allowance		218,391			159,595
Deferred tax liabilities:
Plant and equipment, principally due to differences in depreciation		1,011,963			816,744
Prepaid permits and insurance, principally due to expensing for income tax purposes		55,132			44,132
Lease right-of-use assets		71,827			44,161
Total gross deferred tax liabilities		1,138,922			905,037
Net deferred tax liability	$	920,531		$	745,442

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

	December 31,
	2022			2021			2020
Beginning balance	$	78.5		$	66.1		$	50.6
Additions based on tax positions related to the current year		25.8			14.9			9.8
Additions/(reductions) based on tax positions taken in prior years		2.8			4.8			13.9
Reductions due to settlements		(8.0	)		(0.9	)		(1.0	)
Reductions due to lapse of applicable statute of limitations		(10.0	)		(6.4	)		(7.2	)
Ending balance	$	89.1		$	78.5		$	66.1