Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Provision (Benefit) for Income Taxes

The provision (benefit) for income taxes for the years ended December 31, 2018, 2017 and 2016, consisted of the following (in thousands):

	Years Ended December 31,
	2018			2017		2016
Current:
Federal	$	99,830		$	133,097	$	156,937
State	38,356			24,944		34,927
Foreign	35,007			27,079		20,725
Deferred:
Federal and state	(15,849		)	41,717		(3,785		)
Foreign	(30		)	95		1,917
	$	157,314		$	226,932	$	210,721

Income Before Provision for Income Taxes

Income before the provision for income taxes for the years ended December 31, 2018, 2017 and 2016, consisted of the following (in thousands):

	Years Ended December 31,
	2018		2017		2016
Domestic	$	485,489	$	445,418	$	494,890
Foreign	106,113		72,098		59,220
	$	591,602	$	517,516	$	554,110

Difference of Income Taxes from Statutory Federal Income Tax Rates

The income taxes shown above varied from the statutory federal income tax rates for these periods as follows:

	Years Ended December 31,
	2018		2017		2016
Federal U.S. income tax rate	21.0	%	35.0	%	35.0	%
State income taxes, net of federal tax benefit	4.7		3.7		4.2
Permanent book/tax differences	0.6		0.4		0.5
Non-U.S. income taxed at different rates, net of foreign tax credits	2.0		—		(0.6	)
Federal tax credits	(1.7	)	(1.3	)	(0.8	)
Tax impact of uncertain tax positions	0.8		0.2		—
Valuation allowance release, net	—		—		(0.1	)
Tax effects of TCJA	0.4		6.5		—
Other, net	(1.2	)	(0.6	)	(0.2	)
Effective tax rate	26.6	%	43.9	%	38.0	%

Deferred Portion of Tax Provision (Benefit)

The deferred portion of the tax (benefit) provision consisted of the following (in thousands):

	Years Ended December 31,
	2018			2017			2016
Accrued expenses, deducted for tax when paid	$	(21,884	)	$	15,213		$	(6,889	)
Capitalized costs for books, deducted for tax	(4,832		)	(5,790		)	5,901
Depreciation	10,071			(4,079		)	(2,405		)
Tax effects of TCJA	—			34,633			—
Other, net	766			1,835			1,525
	$	(15,879	)	$	41,812		$	(1,868	)

Components of Deferred Income Tax Amounts

The components of the deferred income tax amounts at December 31, 2018 and 2017, were as follows (in thousands):

	December 31,
	2018			2017
Deferred Income Tax Assets
Deferred compensation and other benefit obligations	$	87,513		$	68,101
Credits and net operating loss carryforwards	31,169			30,087
Stock-based compensation	9,535			8,614
Provision for bad debts	7,891			6,794
Workers’ compensation	3,580			3,127
Other	14,959			13,343
Total deferred income tax assets	154,647			130,066
Deferred Income Tax Liabilities
Amortization of intangible assets	(21,210		)	(20,220		)
Property and equipment basis differences	(9,761		)	(4,421		)
Other	(10,319		)	(10,847		)
Total deferred income tax liabilities	(41,290		)	(35,488		)
Valuation allowance	(23,072		)	(20,178		)
Total deferred income tax assets, net	$	90,285		$	74,400

Reconciliation of Total Amounts of Gross Unrecognized Tax Benefits

The following table reconciles the total amounts of gross unrecognized tax benefits from January 1, 2016 to December 31, 2018 (in thousands):

	December 31,
	2018			2017			2016
Balance at beginning of period	$	2,886		$	731		$	814
Gross increases—tax positions in prior years	3,259			1,503			92
Gross decreases—tax positions in prior years	(8		)	(257		)	—
Gross increases—tax positions in current year	2,284			956			114
Settlements	—			(40		)	—
Lapse of statute of limitations	(3		)	(7		)	(289		)
Balance at end of period	$	8,418		$	2,886		$	731