Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Summary of Income Tax Provision

The income tax provision consists of the following (in thousands):

	2022		2021		2020
Current:
U.S. federal	$	68,934	$	62,222	$	24,311
State		20,058		12,997		5,364
Total current income tax provision		88,992		75,219		29,675
Deferred:
U.S. federal		21,440		3,915		8,255
State		194		404		8
Total deferred income tax provision		21,634		4,319		8,263
Total income tax provision	$	110,626	$	79,538	$	37,938

Summary of Reconciliation Between Income Taxes and Effective Income Tax Provision

A reconciliation between income taxes at the federal statutory rate (21 percent) and the actual income tax provision is as follows (in thousands):

	2022			2021			2020
Provision at federal statutory rate	$	98,290		$	69,856		$	37,018
State income taxes, net of federal benefit		16,274			11,435			5,664
Tax credits		(1,355	)		(1,754	)		(1,424	)
Excess tax benefit on stock compensation		(1,578	)		(793	)		(4,500	)
Other, net		(1,005	)		794			1,180
Total provision	$	110,626		$	79,538		$	37,938

Summary of Gross Unrecognized Tax Benefits

A reconciliation of the beginning and ending total amounts of gross unrecognized tax benefits is as follows (in thousands):

	2022			2021
Gross unrecognized tax benefits at beginning of year	$	1,370		$	1,052
Gross (decreases) increases in tax positions for prior years		1,779			(4	)
Gross increases in tax positions for current year		1,005			598
Settlements		—			(96	)
Lapse of statute of limitations		(287	)		(180	)
Gross unrecognized tax benefits at end of year	$	3,867		$	1,370

Summary of Deferred Tax Liabilities and Assets

Deferred tax (liabilities) assets are comprised of the following at December 31 (in thousands):

	2022			2021
Depreciation	$	(183,276	)	$	(165,405	)
Leases		(30,886	)		(27,876	)
Other		(5,471	)		(4,658	)
Gross deferred tax liabilities		(219,633	)		(197,939	)
Allowance for doubtful accounts		1,435			1,374
Equity-based compensation		4,089			3,626
Employee benefits		9,988			8,516
Leases		30,578			27,357
Claims and insurance		22,137			27,351
Other		5,635			5,578
Gross deferred tax assets		73,862			73,802
Net deferred tax liability	$	(145,771	)	$	(124,137	)