Real Property Acquisitions and Development (Details 2) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Real property acquisitions:
Total cash invested in real property	$ 1,158,266	$ 3,370,597
Investment Percentage Range	10% to 50%
Development projects:
Total development projects	164,833	325,563
Expansion projects	240	19,218
Total construction in progress conversions	165,073	344,781
Medical facilities [Member]
Real property acquisitions:
Properties	19
Development projects:
Total development projects	105,666	325,563
Hospital Facilities [Member]
Real property acquisitions:
Properties	1
Seniors Housing Facilities Operating [Member]
Real property acquisitions:
Properties	48
Seniors Housing Facilities Triple Net [Member]
Real property acquisitions:
Properties	24
Development projects:
Total development projects	$ 59,167	$ 0