Income Taxes (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017, Amount	$ 16.5	$ 315.9	$ 0.0
Tax Cuts and Jobs Act of 2017, change in tax rate, income tax expense (benefit)		$ 371.4
Effective Income Tax Rate Reconciliation, Percent	17.50%	(113.70%)	31.30%
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Amount	$ 1.4	$ 0.0	$ 7.8
State deferred tax rate change impact		5.0	0.0
Provision for Income Taxes, Equity Method Investment	(10.8)	(12.0)	(5.7)
Alternative minimum tax credit	3.4	8.0
State net operating loss	26.4	29.5
State net operating loss carryforwards valuation allowance	12.6	10.3
Foreign net operating loss	2.1	2.1
Unrecognized Tax Benefits	4.3
Decrease in income tax expenses unrecognized tax benefits if recognized	2.8
Tax Cuts and Jobs Act of 2017, transition tax for accumulated roreign earnings, income tax expense (benefit)	23.1	57.2
Tax Cuts and Jobs Act of 2017, change in tax rate, deferred tax liability, income tax (expense) Benefit		$ 5.0
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Equity Method Investment, Summarized Financial Information, Income Tax			$ 3.9
Amount of U.S. federal tax net operating loss	$ 1.8