Income Taxes - Net Operating Losses (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
2019-2023	$ 5.5
2024-2028	3.8
2029 and thereafter	14.3
Unlimited	18.4
Tax benefit of net operating loss carryforwards before valuation allowances	42.0	$ 41.1
Federal
Operating Loss Carryforwards [Line Items]
2019-2023	0.0
2024-2028	0.0
2029 and thereafter	0.0
Unlimited	0.0
Tax benefit of net operating loss carryforwards before valuation allowances	0.0
State
Operating Loss Carryforwards [Line Items]
2019-2023	0.0
2024-2028	0.6
2029 and thereafter	13.9
Unlimited	0.0
Tax benefit of net operating loss carryforwards before valuation allowances	14.5
Foreign
Operating Loss Carryforwards [Line Items]
2019-2023	5.5
2024-2028	3.2
2029 and thereafter	0.4
Unlimited	18.4
Tax benefit of net operating loss carryforwards before valuation allowances	$ 27.5