Prepaid Expenses and Other Assets (Details) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Prepaid Expense and Other Assets [Abstract]    
Construction contract costs incurred in excess of billings $ 19,136,000 $ 6,656,000
Prepaid expenses 14,862,000 20,570,000
Lease incentives, net 13,183,000 13,344,000
Furniture, fixtures and equipment, net 6,349,000 6,637,000
Deposit on acquisitions 5,066,000 516,000
Deferred tax asset, net 3,946,000 4,002,000
Operating notes receivable 3,629,000 3,797,000
Equity method investments 2,390,000 2,368,000
Other assets 2,939,000 2,359,000
Prepaid expenses and other assets 71,500,000 60,249,000
Long-term Operating Notes Receivable    
Mortgage and Other Investing Receivables [Line Items]    
Operating notes receivable 3,600,000 3,600,000
Allowances for estimated losses 281,000 252,000
Taxable REIT Subsidiary    
Mortgage and Other Investing Receivables [Line Items]    
Deferred tax assets, valuation allowance $ 2,100,000 $ 2,100,000