Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Contingency [Line Items]
Effective income tax rates	(9.90%)	(7.70%)
Unrecognized tax benefits	$ 1.5		$ 1.5
Unrecognized tax benefits income tax penalties and interest accrued	0.4		0.4
Unrecognized tax benefits, reduction resulting from lapse of applicable statute of limitations	$ 1.2
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards			630.7
Net operating loss carryforwards, Year of expiration	2024
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards			$ 700.3
Net operating loss carryforwards, Year of expiration	2028