Dispositions, Assets Held for Sale and Discontinued Operations (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real property dispositions:
Property dispositions	$ 448,939,000	$ 521,722,000	$ 186,050,000
Add: Gain (loss) on sales of properties, net	49,138,000	100,549,000	61,160,000
Sellers financing	(3,850,000)	(12,000,000)	0
Non-cash disposition activity	(12,204,000)	0	0
Proceeds from sales of real property	482,023,000	610,271,000	247,210,000
Revenues:
Rental income	18,377,000	96,378,000	124,113,000
Other income	0	0	0
Expenses:
Interest expense	4,246,000	21,735,000	31,018,000
Property operating expenses	3,396,000	4,482,000	8,806,000
Provision for depreciation	8,160,000	27,365,000	37,126,000
Income (loss) from discontinued operations, net	2,575,000	42,796,000	47,163,000
Medical Facilities [Member]
Real property dispositions:
Property dispositions	259,367,000	149,344,000	35,295,000
Seniors Housing Triple-net [Member]
Real property dispositions:
Property dispositions	189,572,000	372,378,000	150,755,000
Seniors Housing Operating [Member]
Real property dispositions:
Property dispositions	$ 0	$ 0	$ 0