Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Income Taxes - Textual (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
Income Taxes - Textual (Details) - USD ($) $ in Millions	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2016
Income Tax Contingency [Line Items]
Provision for income tax expense	$ 28.6	$ 42.4	$ 68.3	$ 82.1
Net deferred tax assets	102.1		102.1
Valuation allowance	28.3		28.3
Additional tax benefits due to approval of accounting method change			56.0		$ 39.0
Gross unrecognized tax benefits	0.3		0.3			$ 2.8
Gross unrecognized tax benefits that would impact effective tax rate if recognized	0.3		0.3			$ 2.8
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards	$ 63.2		$ 63.2