Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Components of the income tax provision applicable to federal, state and foreign income taxes for the years ended December 31, 2020, 2019 and 2018 are as follows (in thousands):

	2020			2019			2018
Federal income tax benefit:
Current	$	(1,977	)	$	(1,976	)	$	(3,954	)
Deferred		(107,334	)		(90,441	)		(35,081	)
		(109,311	)		(92,417	)		(39,035	)
State income tax expense (benefit):
Current		225			851			1,704
Deferred		(17,949	)		(11,593	)		(11,147	)
		(17,724	)		(10,742	)		(9,443	)
Foreign income tax expense (benefit):
Current		(291	)		(348	)		(2,552	)
Deferred	—				(1,168	)		5,043
		(291	)		(1,516	)		2,491
Total income tax benefit:
Current		(2,043	)		(1,473	)		(4,802	)
Deferred		(125,283	)		(103,202	)		(41,185	)
Total income tax benefit:	$	(127,326	)	$	(104,675	)	$	(45,987	)

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

The difference between the statutory federal income tax rate and the effective income tax rate for the years ended December 31, 2020, 2019 and 2018 is summarized as follows:

	2020			2019			2018
Statutory tax rate		21.0	%		21.0	%		21.0	%
State income taxes - net of the federal income tax benefit		1.7			1.4			1.1
Goodwill impairment		(8.2	)		(0.7	)		(6.9	)
Permanent differences		(0.6	)		(1.2	)		(0.7	)
Tax effects of tax reform		—			—			(1.3	)
Valuation allowance		(0.2	)		(0.8	)		(3.7	)
State deferred tax remeasurement		—			(1.1	)		2.3
Other differences, net		—			1.1			0.7
Effective tax rate		13.7	%		19.7	%		12.5	%

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, 2020 and 2019 are as follows (in thousands):

	2020			2019
Deferred tax assets:
Net operating loss carryforwards	$	370,875		$	375,308
Tax credits		4,918			4,138
Expense associated with stock-based compensation		11,252			10,561
Workers' compensation allowance		17,177			19,536
Other deferred tax asset		24,735			21,698
		428,957			431,241
Less:
Valuation allowance		(19,133	)		(17,231	)
Total deferred tax assets		409,824			414,010
Deferred tax liabilities:
Property and equipment basis difference		(475,025	)		(607,785	)
Other		(12,475	)		(9,184	)
Total deferred tax liabilities		(487,500	)		(616,969	)
Net deferred tax liability	$	(77,676	)	$	(202,959	)