Income Taxes (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Valuation allowance
Reversal of tax reserve	$ 0.3
Reversal of accrued interest	$ 0.2
Deferred tax assets valuation allowance		$ 124.0
Percentage of valuation allowance	100.00%
Deferred tax assets, net of valuation allowance	$ 0.0
Accounting Standards Update 2016-09
Valuation allowance
Net excess tax benefits	2.6
Excess tax benefits of deferred tax assets	$ 2.8