Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Components of Income Tax Provision

Components of the income tax provision applicable to federal, state and foreign income taxes for the years ended December 31, 2021, 2020 and 2019 are as follows (in thousands):

	2021			2020			2019
Federal income tax benefit:
Current	$	—		$	(1,977	)	$	(1,976	)
Deferred		(86,878	)		(107,334	)		(90,441	)
		(86,878	)		(109,311	)		(92,417	)
State income tax expense (benefit):
Current		144			225			851
Deferred		23,028			(17,949	)		(11,593	)
		23,172			(17,724	)		(10,742	)
Foreign income tax expense (benefit):
Current		134			(291	)		(348	)
Deferred		870		—				(1,168	)
		1,004			(291	)		(1,516	)
Total income tax benefit:
Current		278			(2,043	)		(1,473	)
Deferred		(62,980	)		(125,283	)		(103,202	)
Total income tax benefit:	$	(62,702	)	$	(127,326	)	$	(104,675	)

Difference Between Statutory Federal Income Tax Rate and Effective Income Tax Rate

The difference between the statutory U.S. federal income tax rate and the effective income tax rate for the years ended December 31, 2021, 2020 and 2019 is summarized as follows:

	2021			2020			2019
Statutory tax rate		21.0	%		21.0	%		21.0	%
State income taxes - net of the federal income tax benefit		3.0			1.7			1.4
Goodwill impairment		—			(8.2	)		(0.7	)
Permanent differences		(0.8	)		(0.6	)		(1.2	)
Valuation allowance		(13.3	)		(0.2	)		(0.8	)
State deferred tax remeasurement		(0.8	)		—			(1.1	)
Other differences, net		(0.4	)		—			1.1
Effective tax rate		8.7	%		13.7	%		19.7	%

Tax Effect of Temporary Differences and Tax Attributes Representing Deferred Tax Assets and Liabilities

The tax effect of temporary differences and tax attributes representing deferred tax assets and liabilities at December 31, 2021 and 2020 are as follows (in thousands):

	2021			2020
Deferred tax assets:
Net operating loss carryforwards	$	457,362		$	370,875
Tax credits		4,453			4,918
Expense associated with stock-based compensation		9,364			11,252
Workers' compensation allowance		14,833			17,177
Other deferred tax asset		26,483			24,735
		512,495			428,957
Less:
Valuation allowance		(189,737	)		(19,133	)
Total deferred tax assets		322,758			409,824
Deferred tax liabilities:
Property and equipment basis difference		(335,980	)		(475,025	)
Other		(12,037	)		(12,475	)
Total deferred tax liabilities		(348,017	)		(487,500	)
Net deferred tax liability	$	(25,259	)	$	(77,676	)