Income Taxes - Details of Scheduled Expiration Dates of Tax Effected Net Operating Loss (NOL) and Other Tax Carryforwards (Details) $ in Millions	Dec. 31, 2018 USD ($)
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	$ 37.7
U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	32.4
U.S. federal tax credit carryforwards	0.1
State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	2.0
U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	3.2
2019 Through 2028
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	33.5
2019 Through 2028 | U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	28.6
2019 Through 2028 | State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	1.8
2019 Through 2028 | U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	3.1
2029 Through 2038
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	4.1
2029 Through 2038 | U.S. federal
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	3.8
U.S. federal tax credit carryforwards	0.1
2029 Through 2038 | State taxing jurisdiction
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Net Operating Loss	0.2
Indefinite
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
Total	0.1
Indefinite | U.S. federal and non-U.S.
Operating Loss Carryforwards And Other Tax Carryforwards [Line Items]
U.S. federal and non-U.S. capital loss carryforwards	$ 0.1