Lease Intangible Assets and Liabilities (Detail) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2013
Dec. 31, 2012
Capital Leased Assets [Line Items]    
Less: accumulated amortization $ (124,183) $ (105,169)
Intangible lease assets, net 614,436 187,362
Less: accumulated amortization (19,882) (16,335)
Intangible lease liabilities, net 213,918 45,603
In-place Leases
   
Capital Leased Assets [Line Items]    
Intangible lease assets, gross 650,126 271,392
Above-Market Lease
   
Capital Leased Assets [Line Items]    
Intangible lease assets, gross 88,493 21,139
Below-Market Leases
   
Capital Leased Assets [Line Items]    
Below-market leases $ 233,800 $ 61,938