Revenues - Performance Obligation (Details) - Professional Services, All Other Contracts - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01	Dec. 31, 2020
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period of expected timing of satisfaction	2 years
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period of expected timing of satisfaction	5 years