Commitments and Contingencies - Construction Activity (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) ft² property	Mar. 31, 2016 property	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2006 USD ($)
Other Commitments [Line Items]
Approximate Square Feet | ft²	14,500,000
Land held for redevelopment	$ 17,438		$ 17,452
ALABAMA
Other Commitments [Line Items]
Total Amount Funded	11,500
Estimated Remaining Fundings	3,900
Estimated Total Investment	15,400
TEXAS
Other Commitments [Line Items]
Number of Properties | property		2
Estimated Remaining Fundings	$ 800
TENNESSEE
Other Commitments [Line Items]
Number of Properties | property	2
Total Amount Funded	$ 39,200
Estimated Total Investment	51,800
Land held for redevelopment	$ 4,300
Medical Office Building Expansion [Member] | TENNESSEE
Other Commitments [Line Items]
Approximate Square Feet | ft²	70,000
Retail Site [Member] | TEXAS
Other Commitments [Line Items]
Total Amount Funded	$ 4,800
Estimated Total Investment	$ 5,600
Approximate Square Feet | ft²			12,900
Land held for redevelopment				$ 1,500
Percentage of property leased	100.00%
Medical Office Building [Member] | TENNESSEE
Other Commitments [Line Items]
Number of Properties | property	2
Construction in Progress, Gross	$ 32,180
Other Amounts Funded	7,050
Total Amount Funded	39,230
Estimated Remaining Fundings	12,570
Estimated Total Investment	$ 51,800
Approximate Square Feet | ft²	294,000
Medical Office Building [Member] | COLORADO
Other Commitments [Line Items]
Number of Properties | property	1
Construction in Progress, Gross	$ 2,994
Other Amounts Funded	0
Total Amount Funded	2,994
Estimated Remaining Fundings	23,506
Estimated Total Investment	$ 26,500
Approximate Square Feet | ft²	98,000
Medical Office Buildings and Retail Sites [Member]
Other Commitments [Line Items]
Construction in Progress, Gross	$ 35,174
Other Amounts Funded	7,050
Total Amount Funded	42,224
Estimated Remaining Fundings	36,076
Estimated Total Investment	$ 78,300
Approximate Square Feet | ft²	392,000