Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Contingency [Line Items]
Effective income tax rate reconciliation, percent	(20.20%)	45.50%	(4.10%)	22.40%
U.S. statutory rate (as a percent)			21.00%	35.00%
Income tax expense (benefit)	$ 2.5	$ (1.0)	$ 3.2	$ (1.3)
Continuing Operations | BAM
Income Tax Contingency [Line Items]
Income tax expense (benefit)	$ (1.6)	$ (2.1)	$ (2.2)	$ (4.8)