Other Liabilities - Performance Obligations (Details) $ in Millions	Sep. 30, 2021 USD ($)
Performance obligations
Remaining performance obligations	$ 19.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Performance obligations
Remaining performance obligations	$ 1.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Performance obligations
Remaining performance obligations	$ 8.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Performance obligations
Remaining performance obligations	$ 6.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Performance obligations
Remaining performance obligations	$ 3.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period