Commitments and Contingencies - Construction Activity (Details) $ in Millions	Sep. 30, 2019 USD ($) ft²
Other Commitments [Line Items]
Approximate Square Feet | ft²	15,400,000
Medical Office Building Expansion | North Carolina
Other Commitments [Line Items]
Approximate Square Feet | ft²	40,278
Medical Office Building | North Carolina
Other Commitments [Line Items]
Total amount funded	$ 9.8
Estimated amount to complete project	$ 2.2
Medical Office Building | Washington
Other Commitments [Line Items]
Approximate Square Feet | ft²	151,000
Total amount funded	$ 44.3
Estimated amount to complete project	$ 19.8