Commitments and Contingencies - Guarantees (Details) - Financial Guarantee $ in Thousands	Jun. 30, 2020 USD ($)
Commitments and Contingencies
Guarantor obligations, maximum exposure (up to)	$ 62,725
The Residences at Annapolis Junction
Commitments and Contingencies
Guarantor obligations, maximum exposure (up to)	8,300
Delray Plaza
Commitments and Contingencies
Guarantor obligations, maximum exposure (up to)	5,180
Nexton Square
Commitments and Contingencies
Guarantor obligations, maximum exposure (up to)	12,600
Interlock Commercial
Commitments and Contingencies
Guarantor obligations, maximum exposure (up to)	34,300
Interlock-Fletcher Row (1)
Commitments and Contingencies
Guarantor obligations, maximum exposure (up to)	$ 2,345