General - Accounts Receivable, Contract Assets and Contract Liabilities - Performance Obligation (Details) $ in Millions	Sep. 30, 2021 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Performance obligation
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	3 months
Estimated revenue to be recognized	$ 2.1
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Performance obligation
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Estimated revenue to be recognized	$ 6.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Performance obligation
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Estimated revenue to be recognized	$ 4.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Performance obligation
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	0 months
Estimated revenue to be recognized	$ 5.8