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Construction Contract and Other Service Revenues - Narrative (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Construction Contract Revenue        
Disaggregation of Revenue [Line Items]        
Deferred incremental costs incurred $ 0 $ 0 $ 0 $ 0