Commitments and Contingencies - Construction Activity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) ft² parking_space property	Dec. 31, 2015 USD ($)	Sep. 30, 2015 ft²	Dec. 31, 2006 USD ($)
Other Commitments [Line Items]
Approximate Square Feet | ft²	14,300,000
Land held for redevelopment	$ 17,434	$ 17,452
ALABAMA
Other Commitments [Line Items]
Total Amount Funded	10,700
Estimated Remaining Fundings	4,700
Estimated Total Investment	$ 15,400
TEXAS
Other Commitments [Line Items]
Number of Properties | property	2
TENNESSEE
Other Commitments [Line Items]
Number of Properties | property	2
Total Amount Funded	$ 32,600
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]
Number of Properties | property	1
Construction in Progress, Gross	$ 4,614
Other Amounts Funded	0
Total Amount Funded	4,614
Estimated Remaining Fundings	961
Estimated Total Investment	$ 5,575
Approximate Square Feet | ft²	12,900		12,900
Land held for redevelopment				$ 1,500
Medical Office Building [Member] | ALABAMA
Other Commitments [Line Items]
Number of Properties | property	1
Construction in Progress, Gross	$ 0
Other Amounts Funded	10,705
Total Amount Funded	10,705
Estimated Remaining Fundings	4,695
Estimated Total Investment	$ 15,400
Approximate Square Feet | ft²	138,000
Medical Office Building [Member] | TENNESSEE
Other Commitments [Line Items]
Number of Properties | property	2
Construction in Progress, Gross	$ 26,185
Other Amounts Funded	6,423
Total Amount Funded	32,608
Estimated Remaining Fundings	19,192
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	$ 870
Other Amounts Funded	0
Total Amount Funded	870
Estimated Remaining Fundings	25,630
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	$ 31,669
Other Amounts Funded	17,128
Total Amount Funded	48,797
Estimated Remaining Fundings	50,478
Estimated Total Investment	$ 99,275
Approximate Square Feet | ft²	542,900
Tenant Improvement Allowances [Member] | Medical Office Building [Member] | ALABAMA
Other Commitments [Line Items]
Estimated Total Investment	$ 9,500
812930 Parking Lots and Garages [Member] | Medical Office Building [Member] | ALABAMA
Other Commitments [Line Items]
Estimated Total Investment	$ 5,900
Number of parking spaces | parking_space	400