Summary of Significant Accounting Policies (Details) (USD $)	6 Months Ended
	Jun. 30, 2011
Summary of Significant Accounting Policies (Textuals) [Abstract]
Gross investment, amount, total	$ 2,739,117,000
Number of investments, total whole units	216
Number of states that the Company owns real estate in, whole units	28
Number of investments, whole units	203
Square Feet, whole units	13,400,000
Number of investments, whole units	1
Number of facility types	3
Number of construction mortgages loans	3
Aggregate amount of construction mortgage loans	45,900,000
Approximate square feet for which Nationwide property management services provided by company	9,200,000
Number of consolidated joint ventures with same joint venture partner	2
Number of real estate properties subject to property operating agreements	8
Condition to qualify as a REIT	Must distribute at least 90% per annum of its REIT taxable income to its stockholders and meet other requirements
Number of employees covered by the Company's pension plan	3
Maximum annual benefits payable under the executive retirement plan	896,000,000
Defined Benefit Plan, Measurement Date	December,31
Amount paid for termination of plan in during 2009 and during 2010	2,600,000
Leases, Acquired-in-Place [Member]
Summary of Significant Accounting Policies (Textuals) [Abstract]
Elimination of real estate lease intangibles against accumulated depreciation	$ 40,000,000
HR Ladco Holdings, LLC [Member]
Summary of Significant Accounting Policies (Textuals) [Abstract]
Number of consolidated joint ventures	80.00%
Lakewood MOB, LLC [Member]
Summary of Significant Accounting Policies (Textuals) [Abstract]
Number of consolidated joint ventures	98.75%