Fair Value Measurements (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Short term investments	$ 3.3		$ 22.0
Clinton Group
Schedule of Available-for-sale Securities [Line Items]
Short term investments	2.5		$ 19.5
Decrease in short term investment balance	17.0
Redemptions	16.5
Accrued fees		$ 0.4
Clinton Group | Other (income) expense
Schedule of Available-for-sale Securities [Line Items]
Unrealized holding loss	$ 0.5	$ 0.3