Leases - Operating leases (Details) $ in Millions	Jun. 30, 2019 USD ($)
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining)	$ 3.7
2020	6.1
2021	3.8
2022	2.4
2023	1.9
Thereafter	7.6
Total undiscounted operating lease payments	25.5
Less imputed interest	(3.7)
Present value of operating lease liabilities	21.8
Assets and Liabilities, Lessee [Abstract]
Present value of operating lease liabilities	$ 21.8
Weighted average remaining lease term	5 years 9 months
Weighted average discount rate, percent	4.80%
Other assets
Operating lease, right of use asset	$ 18.4
Accrued liabilities
Operating lease, current liability	6.1
Other liabilities
Operating lease, noncurrent liability	$ 15.7