Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Summary of Tax Expenses

Income taxes are summarized as follows:

	Year ended December 31,
	2017			2016		2015
	(in thousands)
Current:
Federal	$	116,400		$	24,208	$	94,036
State		9,382			1,943		3,636
Foreign		11,533			10,806		10,589
		137,315			36,957		108,261
Deferred:
Federal		(104,062	)		91,190		33,446
State		(10,724	)		3,753		3,413
Foreign		939			2,205		(1,225	)
		(113,847	)		97,148		35,634
	$	23,468		$	134,105	$	143,895

Schedule of Effective Income Tax Rate Reconciliation

Income taxes differ from the amounts computed by applying the federal income tax rate of 35.0%. A reconciliation of these differences is as follows:

	Year ended December 31,
		2017					2016					2015
	(in thousands, except percentages)
Taxes calculated at federal rate	$	155,866		35.0	%	$	167,153		35.0	%	$	151,468		35.0	%
State taxes, net of federal benefit		(872	)	(0.2	)		3,703		0.8			4,581		1.1
Change in liability for tax positions		(3,482	)	(0.8	)		(10,512	)	(2.2	)		1,094		0.3
Foreign income taxed at different rates		(6,163	)	(1.3	)		(7,983	)	(1.7	)		(7,111	)	(1.6	)
Federal tax credits		—		—			(12,265	)	(2.6	)		(1,710	)	(0.4	)
Tax reform impact		(129,139	)	(29.0	)		—		—			—		—
Unremitted foreign earnings		14,997		3.3			—		—			—		—
Other items, net		(7,739	)	(1.7	)		(5,991	)	(1.2	)		(4,427	)	(1.1	)
	$	23,468		5.3	%	$	134,105		28.1	%	$	143,895		33.3	%

Net Deferred Tax (Liability) Assets

The primary components of temporary differences that give rise to the Company’s net deferred tax liability are as follows:

	December 31,
	2017			2016
	(in thousands)
Deferred tax assets:
Deferred revenue	$	7,766		$	11,966
Employee benefits		86,519			83,100
Bad debt reserves		7,191			12,704
Loss reserves		1,372			1,974
Pension		22,600			89,726
Net operating loss carryforward		13,914			14,358
Securities		—			10,664
Foreign tax credit		7,976			4,086
Other		5,673			7,557
		153,011			236,135
Valuation allowance		(10,333	)		(8,049	)
		142,678			228,086
Deferred tax liabilities:
Depreciable and amortizable assets		204,863			320,884
Claims and related salvage		104,323			121,812
Investments in affiliates		3,343			7,511
Securities		11,656			—
Unremitted foreign earnings		14,997			—
		339,182			450,207
Net deferred tax liability	$	196,504		$	222,121

Changes in Unrecognized Tax Benefits

A reconciliation of the beginning and ending amounts of unrecognized tax benefits for the years ended December 31, 2017, 2016 and 2015 is as follows:

	December 31,
	2017			2016			2015
	(in thousands)
Unrecognized tax benefits—beginning balance	$	18,100		$	23,800		$	24,100
Gross decreases—prior period tax positions		(1,000	)		(7,100	)		(800	)
Gross increases—current period tax positions		—			1,400			500
Settlements with taxing authorities		(4,300	)		—			—
Unrecognized tax benefits—ending balance	$	12,800		$	18,100		$	23,800