Acquisitions, Dispositions and Mortgage Repayments - Dispositions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 sqft		Dec. 31, 2013 sqft
Real Estate Dispositions [Line Items]
Sales Price	$ 34.9		$ 101.9
Closing Adjustments	(0.7)		(1.5)
Mortgage Notes	3.0		(3.7)
Net Proceeds	37.2		96.7
Net Real Estate Investment	28.2		76.7
Other (including receivables)	0.5		2.3
Gain/ (Impairment)	5.5		21.4
Square Footage	476,536.0		541,502.0
Real estate dispositions [Member]
Real Estate Dispositions [Line Items]
Sales Price	34.9		101.9
Closing Adjustments	(0.7)		(1.5)
Mortgage Notes	(1.9)		(4.3)
Net Proceeds	32.3		96.1
Net Real Estate Investment	28.2		76.7
Other (including receivables)	0.5		2.3
Gain/ (Impairment)	5.5		21.4
Square Footage	476,536.0		541,502.0
Mortgage note repayments [Member]
Real Estate Dispositions [Line Items]
Mortgage Notes	4.9		0.6
Net Proceeds	4.9		0.6
Pennsylvania [Member] | Pennsylvania One [Member] | Real estate dispositions [Member] | Inpatient Facility Disposed September 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Sep. 30, 2013
Sales Price			17.6
Closing Adjustments			(0.3)
Net Proceeds			17.3
Net Real Estate Investment			12.2
Gain/ (Impairment)			5.1
Square Footage			76,324.0
Pennsylvania [Member] | Pennsylvania Two [Member] | Real estate dispositions [Member] | Inpatient Facility Disposed September 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Sep. 30, 2013
Sales Price			17.6
Closing Adjustments			(0.4)
Net Proceeds			17.2
Net Real Estate Investment			12.6
Gain/ (Impairment)			4.6
Square Footage			79,560.0
North Carolina [Member] | Real estate dispositions [Member]
Real Estate Dispositions [Line Items]
Net Real Estate Investment			13.4
Square Footage			57,580.0
North Carolina [Member] | Real estate dispositions [Member] | Medical Building Disposed December 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Dec. 05, 2013
Sales Price			17.6
Net Proceeds			17.6
Net Real Estate Investment			13.4
Other (including receivables)			2.1
Gain/ (Impairment)			2.1
Square Footage			57,580.0
Alabama [Member] | Real estate dispositions [Member]
Real Estate Dispositions [Line Items]
Net Proceeds			1.9
Net Real Estate Investment			1.4
Gain/ (Impairment)			0.5
Square Footage			10,593.0
Alabama [Member] | Real estate dispositions [Member] | Inpatient Facility Disposed July 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Jul. 31, 2013
Sales Price			17.5	[1]
Closing Adjustments			(0.1)	[1]
Net Proceeds			17.4	[1]
Net Real Estate Investment			11.2	[1]
Gain/ (Impairment)			6.2	[1]
Square Footage			82,000.0	[1]
Alabama [Member] | Real estate dispositions [Member] | Medical Building Disposed December 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Dec. 31, 2013
Sales Price			1.9	[1]
Net Proceeds			1.9	[1]
Net Real Estate Investment			1.4	[1]
Gain/ (Impairment)			0.5	[1]
Square Footage			10,593.0	[1]
Florida [Member] | Real estate dispositions [Member]
Real Estate Dispositions [Line Items]
Net Real Estate Investment			0.8
Square Footage			14,322.0
Florida [Member] | Real estate dispositions [Member] | Medical Building Disposed April 11 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Apr. 11, 2014
Sales Price	1.8	[1]
Closing Adjustments	(0.1)	[1]
Net Proceeds	1.7	[1]
Net Real Estate Investment	1.7	[1]
Square Footage	52,608.0	[1]
Florida [Member] | Real estate dispositions [Member] | Inpatient Facility Disposed July 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Jul. 15, 2013
Sales Price			11.9	[1]
Closing Adjustments			(0.2)	[1]
Net Proceeds			11.7	[1]
Net Real Estate Investment			7.4	[1]
Gain/ (Impairment)			4.3	[1]
Square Footage			62,782.0	[1]
Florida [Member] | Real estate dispositions [Member] | Inpatient Facility Disposed October 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Oct. 31, 2013
Sales Price			0.8	[1]
Net Proceeds			0.8	[1]
Net Real Estate Investment			0.8	[1]
Square Footage			14,322.0	[1]
Iowa [Member] | Medical Building Disposed June 2013 [Member]
Real Estate Dispositions [Line Items]
Real Estate Dispositions Mortgage Note Receivable			1.1
Payments of Debt Extinguishment Costs			0.3
Iowa [Member] | Real estate dispositions [Member] | Medical Building Disposed June 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Jun. 03, 2013
Sales Price			6.9	[2],[3]
Net Proceeds			6.9	[2],[3]
Net Real Estate Investment			5.3	[2],[3]
Other (including receivables)			0.2	[2],[3]
Gain/ (Impairment)			1.4	[2],[3]
Square Footage			31,725.0	[2],[3]
Number of properties sold			2
Real Estate Dispositions Mortgage Note Receivable			1.1
Payments of Debt Extinguishment Costs			0.3
Tennessee [Member] | Building Disposed April 2013 [Member]
Real Estate Dispositions [Line Items]
Sales Price			0.6
Net Real Estate Investment			0.4
Square Footage			17,696.0
Tennessee [Member] | Real estate dispositions [Member] | Medical Building Disposed November 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Nov. 14, 2014
Sales Price	3.1	[3]
Closing Adjustments	(0.2)	[3]
Net Proceeds	2.9	[3]
Net Real Estate Investment	3.2	[3]
Other (including receivables)	0.1	[3]
Gain/ (Impairment)	(0.4)	[3]
Square Footage	32,204.0	[3]
Tennessee [Member] | Real estate dispositions [Member] | Building Disposed April 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Apr. 30, 2013
Sales Price			0.6	[1],[4]
Mortgage Notes			(0.6)	[1],[4]
Net Real Estate Investment			0.4	[1],[4]
Gain/ (Impairment)			0.2	[1],[4]
Square Footage			17,696.0	[1],[4]
Texas [Member] | Real estate dispositions [Member] | Medical Building Disposed April 23 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Apr. 23, 2014
Sales Price	4.4	[1]
Closing Adjustments	(0.2)	[1]
Net Proceeds	4.2	[1]
Net Real Estate Investment	4.1	[1]
Other (including receivables)	0.1	[1]
Square Footage	58,365.0	[1]
Texas [Member] | Real estate dispositions [Member] | Medical Building Disposed November 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Nov. 25, 2014
Sales Price	21.5	[3]
Net Proceeds	21.5	[3]
Net Real Estate Investment	12.1	[3]
Other (including receivables)	0.2	[3]
Gain/ (Impairment)	9.2	[3]
Square Footage	166,167.0	[3]
Texas [Member] | Real estate dispositions [Member] | Land Disposed March 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			Mar. 25, 2013
Sales Price			5.0
Closing Adjustments			(0.2)
Mortgage Notes			(3.7)
Net Proceeds			1.1
Net Real Estate Investment			8.1
Gain/ (Impairment)			(3.3)
Square Footage			15.1
Texas [Member] | Real estate dispositions [Member] | Medical Building Disposed May 15 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			May 15, 2013
Sales Price			1.3
Closing Adjustments			(0.1)
Net Proceeds			1.2
Net Real Estate Investment			0.9
Gain/ (Impairment)			0.3
Square Footage			8,000.0
Texas [Member] | Real estate dispositions [Member] | Medical Building Disposed May 24 2013 [Member]
Real Estate Dispositions [Line Items]
Date Disposed			May 24, 2013
Sales Price			3.2	[1]
Closing Adjustments			(0.2)	[1]
Net Proceeds			3.0	[1]
Net Real Estate Investment			3.0	[1]
Square Footage			100,920.0	[1]
Nevada [Member] | Real estate dispositions [Member] | Medical Building Disposed September 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Sep. 12, 2014
Sales Price	2.3
Closing Adjustments	(0.2)
Mortgage Notes	(1.9)
Net Proceeds	0.2
Net Real Estate Investment	4.9
Gain/ (Impairment)	(2.8)
Square Footage	31,026.0
Missouri [Member] | Real estate dispositions [Member] | Medical Building Disposed December 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Dec. 18, 2014
Sales Price	1.3	[1]
Net Proceeds	1.3	[1]
Net Real Estate Investment	1.4	[1]
Other (including receivables)	0.1	[1]
Gain/ (Impairment)	(0.2)	[1]
Square Footage	26,166.0	[1]
Illinois [Member] | Real estate dispositions [Member] | Medical Building Disposed December 2014 [Member]
Real Estate Dispositions [Line Items]
Date Disposed	Dec. 29, 2014
Sales Price	0.5	[1]
Net Proceeds	0.5	[1]
Net Real Estate Investment	0.8	[1]
Gain/ (Impairment)	$ (0.3)	[1]
Square Footage	110,000.0	[1]

[1] Previously included in assets held for sale.

[2] The Company repaid a mortgage note payable of $1.1 million upon sale and incurred debt extinguishment costs of $0.3 million.

[3] Includes two properties.

[4] The Company-financed mortgage note receivable was repaid in October 2013.