Revenue from Contracts with Customers - Future Fixed Revenue from Stewardship and Real Estate Development Services (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Total Remaining Unsatisfied Performance Obligations	$ 13,825
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-04-01
Revenue from Contract with Customer [Abstract]
Total Remaining Unsatisfied Performance Obligations	$ 7,147
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Total Remaining Unsatisfied Performance Obligations	$ 3,695
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Total Remaining Unsatisfied Performance Obligations	$ 1,691
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Total Remaining Unsatisfied Performance Obligations	$ 1,292
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period