Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Contingency [Line Items]
Provisional tax expense			$ 0.5
Provisional tax liability	$ 0.3
Effective tax rate (as a percent)	(38.40%)	(13.00%)
Statutory tax rate	21.00%