Commitments and Contingencies - Lease Commitments (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) renewal_option	Jun. 30, 2016 USD ($)
Operating Leased Assets [Line Items]
Operating leases, rent expense	$ 1.2	$ 0.2	$ 1.8	$ 0.4
Minimum
Operating Leased Assets [Line Items]
Operating leases, renewal term			5 years
Maximum
Operating Leased Assets [Line Items]
Operating leases, renewal term			10 years
Corporate Headquarters, Office Lease
Operating Leased Assets [Line Items]
Operating leases, renewal term			5 years
Operating lease term			83 months
Operating lease, number of renewal options | renewal_option			3
Rent expense	$ 0.3