Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Rental expense	$ 17.3	$ 13.3	$ 7.6
Rent expense for sublease rentals	3.0	$ 1.7	$ 1.4
Purchase obligations	0.3
Financial Standby Letter of Credit
Other Commitments [Line Items]
Letters of credit outstanding, amount	0.5
Office Lease | Financial Standby Letter of Credit
Other Commitments [Line Items]
Letters of credit outstanding, amount	$ 2.9