Bradley Arrangement - Deficiency Payments, Net of Reimbursements (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Gain Contingency [Roll Forward]
Balance at the beginning of the year	$ 7.8
Deficiency payments made	0.1
Deficiency repayment received	(0.7)
Balance at the beginning of the year	$ 7.2