Fixed Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 2.0	$ 2.2	$ 2.8
Rent expense	3.1	2.9	3.0
Sublease rental income	$ 0.1	$ 0.2	$ 0.2