Commitments and Contingencies - Construction Activity (Details) $ in Millions	Jun. 30, 2019 USD ($) ft²
Other Commitments [Line Items]
Approximate Square Feet | ft²	15,300,000
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	$ 37.3
Estimated amount to complete project	$ 26.8