Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Summary of Components of Company's Income Tax Provision (Benefit) from Continuing Operations

The components of the Company’s income tax provision:

	Year Ended								One month ended
	December 31,			December 31,		November 30,			December 31,
	2017			2016		2015			2015
	(In millions)
Current
U.S. federal	$	(30.6	)	$	3.2	$	33.0		$	7.9
State and local	1.0			3.2		3.4			1.2
	(29.6		)	6.4		36.4			9.1
Deferred
U.S. federal	116.0			2.8		(41.2		)	(6.2		)
State and local	9.7			2.0		5.1			(0.9		)
	125.7			4.8		(36.1		)	(7.1		)
Income tax provision	$	96.1		$	11.2	$	0.3		$	2.0

Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate to Effective Income Tax Rate on Earnings

The following table shows the reconciling items between the income tax provision using the U.S. federal statutory rate and the Company's reported income tax provision.

	Year Ended									One month ended
	December 31,			December 31,			November 30,			December 31,
	2017			2016			2015			2015
Statutory U.S. federal income tax - provision (benefit)	$	30.4		$	10.2		$	(5.6	)	$	3.1
State income taxes	7.0			3.2			5.9			0.4
Reserve adjustments	(4.6		)	(0.3		)	0.4			—
Non-deductible convertible subordinated notes interest	—			0.8			1.4			0.1
R&D credits	(1.2		)	(4.1		)	—			(0.2		)
Retroactive change in federal tax law	—			—			(1.9		)	(1.7		)
Benefit of manufacturing deductions	—			0.5			(1.0		)	(0.6		)
Lobbying costs	0.7			0.8			0.6			—
Deferred tax adjustment	(0.1		)	(0.4		)	—			0.7
Stock compensation excess tax benefits	(1.4		)	—			—			—
Other, net	0.7			0.5			0.5			0.2
New legislation - tax rate changes	64.6			—			—			—
Income tax provision	$	96.1		$	11.2		$	0.3		$	2.0

A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate on earnings in percentages was as follows:

	Year Ended						One month ended
	December 31,		December 31,		November 30,		December 31,
	2017		2016		2015		2015
Statutory U.S. federal income tax rate	35.0	%	35.0	%	(35.0	)%	35.0	%
State income taxes	8.0		11.0		35.2		4.9
Reserve adjustments	(5.3	)	(1.0	)	2.2		(0.3	)
Non-deductible convertible subordinated notes interest	—		2.7		8.0		1.2
R&D credits	(1.4	)	(14.0	)	—		(2.8	)
Retroactive change in federal tax law	—		—		(11.6	)	(19.4	)
Benefit of manufacturing deductions	—		1.7		(5.8	)	(7.0	)
Lobbying costs	0.8		2.7		3.6		0.4
Deferred tax adjustment	(0.1	)	(1.4	)	—		7.8
Stock compensation excess tax benefits	(1.6	)	—		—		—
Other, net	0.8		1.7		5.3		2.4
New legislation - tax rate changes	74.4		—		—		—
Effective income tax rate	110.6	%	38.4	%	1.9	%	22.2	%

Schedule of Reconciliation of Change in Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits consisted of the following:

	Year Ended									One month ended
	December 31,			December 31,			November 30,			December 31,
	2017			2016			2015			2015
	(In millions)
Balances at beginning of fiscal year	$	29.5		$	7.1		$	6.8		$	6.7
Increases based on tax positions in prior years	1.0			25.8			1.0			0.6
Decreases based on tax position in prior years	(25.1		)	(1.2		)	(1.8		)	(0.2		)
Increases based on tax positions in current year	0.4			0.7			0.7			—
Lapse of statute of limitations	(1.4		)	(2.9		)	—			—
Balances at end of fiscal year	$	4.4		$	29.5		$	6.7		$	7.1

Summary of Deferred Tax Assets and Liabilities

Deferred tax assets and liabilities were as follows:

	As of December 31,
	2017			2016
	(In millions)
Deferred Tax Assets
Accrued estimated costs	$	56.1		$	82.0
Basis difference in assets and liabilities	2.1			8.5
Tax losses and credit carryforwards	12.9			6.5
Net cumulative defined benefit pension plan losses	114.7			212.9
Retiree medical and life insurance benefits	9.2			16.2
Valuation allowance	(1.7		)	(1.7		)
Total deferred tax assets	193.3			324.4
Deferred Tax Liabilities
Revenue recognition differences	40.4			21.7
Basis differences in intangible assets	7.1			10.2
Total deferred tax liabilities	47.5			31.9
Total net deferred tax assets	$	145.8		$	292.5

Summary of Changes in Valuation Allowance

The changes in the Company's valuation allowance by period was as follows:

	Balance at Beginning of Period		Tax Valuation Allowance Charged to Income Tax Provision		Tax Valuation Allowance Credited to Income Tax Provision			Balance at End of Period
	(In millions)
Fiscal 2017	$	1.7	$	—	$	—		$	1.7
Fiscal 2016	1.2		0.5		—			1.7
One month ended December 31, 2015	1.7		—		(0.5		)	1.2
Fiscal 2015	2.6		0.6		(1.5		)	1.7