Interest Expense and Related Borrowings (Detail) (USD $)
3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Schedule Of Interest Expenses [Line Items]          
Amortization of deferred financing costs $ 2,327,000 [1] $ 837,000 [1] $ 12,457,000 [1] $ 2,550,000 [1]  
Amortization of net losses related to interest rate swap 0 1,081,000 0 3,415,000  
Amortization of debt discount     5,588,000 7,726,000  
Total interest expense 50,386,000 41,975,000 126,376,000 122,938,000  
Deferred finance costs, net 12,500,000   12,500,000   3,800,000
Proposed Merger
         
Schedule Of Interest Expenses [Line Items]          
Amortization of deferred financing costs     9,500,000    
Term Loan Payable Net
         
Schedule Of Interest Expenses [Line Items]          
Interest expense 0 6,210,000 0 19,925,000  
Revolving Credit Facilities
         
Schedule Of Interest Expenses [Line Items]          
Interest expense 1,196,000 0 1,572,000 0  
Deferred finance costs, net 4,200,000   4,200,000    
Mortgages and Notes Payable
         
Schedule Of Interest Expenses [Line Items]          
Interest expense 47,196,000 29,879,000 106,284,000 89,313,000  
Other Interest Expense
         
Schedule Of Interest Expenses [Line Items]          
Interest expense 8,000 1,000 475,000 9,000  
Interest Expense
         
Schedule Of Interest Expenses [Line Items]          
Amortization of debt discount $ (341,000) [2] $ 3,967,000 [2] $ 5,588,000 [2] $ 7,726,000 [2]  
[1] Includes $9.5 million arising from financing commitments related to the Merger for the nine months ended September 30, 2013.
[2] Income recognized for the three months ended September 30, 2013 is attributable to the amortization of debt premiums recorded on debt assumed in the Merger and recorded at fair value under purchase accounting.