Leases - Narratives (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) facility	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)
Leases [Abstract]
Right of use assets	$ 29.0	$ 34.0		$ 34.8
Operating lease liability	28.7	34.1		$ 34.8
Operating lease liabilities, current	$ 5.1	6.3
Weighted average lease term	5 years 9 months 18 days
Operating lease weighted average discount rate (percent)	2.30%
Operating lease rent expense	$ 11.1	$ 10.2
Operating lease rent expense			$ 7.3
Leased facilities | facility	7