Basis of Presentation and Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax Treatment Of Dividend [Line Items]
Minimum Percentage of Taxable Income Distributed As Dividends	90.00%
Deferred Tax Assets, Valuation Allowance	$ 94,100,000	$ 87,800,000
Income Tax Liability Relating to Taxable REIT Subsidiaries Current	10,777,000	9,608,000	20,336,000
Net Basis Difference Of Assets And Liabilities Between Tax Basis And GAAP Basis	$ 3,600,000,000
Ordinary Income [Member]
Tax Treatment Of Dividend [Line Items]
Percentage Of Taxable Income Distributed	100.00%		62.70%
Long Term Capital Gain [Member]
Tax Treatment Of Dividend [Line Items]
Percentage Of Taxable Income Distributed			37.30%