Summary of Intangible Assets Subject to Amortization in Period of Acquisition (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
In-Place Leases
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired finite lived intangible asset, fair value	$ 1,750	$ 2,511
Acquired finite lived intangible asset, weighted average life	118 months	56 months
Tenant Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired finite lived intangible asset, fair value	1,012	1,553
Acquired finite lived intangible asset, weighted average life	178 months	116 months
Above Market Leases
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired finite lived intangible asset, fair value		2,883
Acquired finite lived intangible asset, weighted average life		56 months
Below Market Leases
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired finite lived intangible asset, fair value	$ (102)
Acquired finite lived intangible asset, weighted average life	116 months