Dispositions (Details)		2 Months Ended	12 Months Ended
	Aug. 17, 2015 USD ($) property	Feb. 13, 2017 USD ($) property	Dec. 31, 2016 USD ($) property	Dec. 31, 2015 USD ($) property loan	Dec. 31, 2014 USD ($) property	Feb. 29, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Debt instrument, face amount						$ 200,000,000
Impairment of real estate			$ 35,200,000	$ 42,200,000	$ 56,600,000
Impairment of assets to be disposed of			0	13,000,000	1,500,000
Issuance of debt related to CCP spin-off			0	1,400,000,000	0
Repayment of debt			1,022,113,000	1,435,596,000	1,151,395,000
Cash distribution to common stockholders			1,024,968,000	1,003,413,000	875,614,000
2016 Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate properties including termination fees			300,800,000
Net gain on the sales of assets			$ 98,200,000
2016 Dispositions | Triple-net leased properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property			29
2016 Dispositions | Senior living operations | Seniors Housing Communities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property			1
2016 Dispositions | Office operations | Medical Office Buildings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property			6
2015 Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate properties including termination fees				541,000,000
Lease termination fees				6,000,000.0
Net gain on the sales of assets				46,300,000
Deferred gain on sale of property				$ 27,400,000
2015 Dispositions | Triple-net leased properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property				39
2015 Dispositions | Office operations | Medical Office Buildings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property				26
2014 Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate properties including termination fees					118,200,000
Net gain on the sales of assets					1,500,000
Gain from sale of assets					$ 21,300,000
2014 Dispositions | Triple-net leased properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property					16
2014 Dispositions | Senior living operations | Seniors Housing Communities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property					2
2014 Dispositions | Office operations | Medical Office Buildings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property					4
CCP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount charge for Service Fee				$ 2,500,000
Income related to Service Fee			$ 1,600,000	900,000
Dispositions 2015, Not Including Care Capital Properties Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income from discontinued operations			0	1,000,000	$ 5,100,000
Spinoff | CCP
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on the sales of assets			0	0	0
Number of real estate contributed to spin-off | property	355
Shares received from spinoff	0.25
Issuance of debt related to CCP spin-off	$ 1,400,000,000
Dividends received	1,300,000,000
Repayment of debt	1,100,000,000
Cash distribution to common stockholders	$ 200,000,000
Transaction cost due to discontinued operations				42,300,000	200,000
Stock-based compensation				3,500,000
Capital and development project expense			0	21,800,000	17,200,000
Net income from discontinued operations			$ (922,000)	$ 10,104,000	$ 94,629,000
Secured Debt
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of loans | loan				1
Debt instrument, face amount				$ 78,400,000
Non-mortgaged
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of loans | loan				1
Debt instrument, face amount				$ 20,000,000
Subsequent Event | 2017 Dispositions
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate properties including termination fees		$ 85,000,000
Net gain on the sales of assets		$ 43,300,000
Subsequent Event | 2017 Dispositions | Triple-net leased properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property		5