Commitments and Contingencies - Construction Activity (Details) $ in Millions	Mar. 31, 2017 USD ($) ft²
Other Commitments [Line Items]
Approximate Square Feet | ft²	14,300,000
Medical Office Building Expansion | TENNESSEE
Other Commitments [Line Items]
Approximate Square Feet | ft²	70,000
Total amount funded	$ 7.5
Tenant improvements included in construction funded	1.9
Construction activity, estimated remaining fundings	$ 3.8
Medical Office Building | COLORADO
Other Commitments [Line Items]
Approximate Square Feet | ft²	98,000
Total amount funded	$ 16.1
Estimated total investment	$ 26.5