Investment in Real Estate - Fair Value Measurements on Non-Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Fair Value Assets Measured On Nonrecurring Basis [Line Items]
Long-lived Assets Sold Impairment	$ (1,511)	[1]
Long Lived Assets Held And Used Impairment	(39)	[1]
Long-lived Assets Impairment	(1,550)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets Measured On Nonrecurring Basis [Line Items]
Long-Lived Assets Held for Sale or Sold	0	[1]
Long-lived Assets Held and Used	0	[1]
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets Measured On Nonrecurring Basis [Line Items]
Long-Lived Assets Held for Sale or Sold	0	[1]
Long-lived Assets Held and Used	0	[1]
Unobservable Inputs (Level 3) [Member]
Fair Value Assets Measured On Nonrecurring Basis [Line Items]
Long-Lived Assets Held for Sale or Sold	28,457	[1]
Long-lived Assets Held and Used	8,303	[1]
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Assets Measured On Nonrecurring Basis [Line Items]
Long-Lived Assets Held for Sale or Sold	28,457	[1]
Long-lived Assets Held and Used	$ 8,303	[1]

[1] Excludes industrial properties for which an impairment reversal of $304 was recorded during the three months ended March 31, 2012, since the related assets are recorded at carrying value, which is lower than estimated fair value at March 31, 2012.