Summarized Operating Results and Financial Position of Unconsolidated Entities (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
OPERATING RESULTS
Revenue	$ 63,120	$ 60,766	$ 56,131	$ 55,449	$ 53,838	$ 54,370	$ 49,318	$ 45,259	$ 235,466	$ 202,785	$ 117,748
Expenses
Depreciation and amortization									61,853	55,936	34,419
Interest expense									57,328	54,580	43,251
Total expenses									163,560	146,442	75,326
Net loss	28,577	2,817	1,689	1,856	344	3,052	219	(698)	34,939	2,917
Our share of net loss										(188)	(4,406)
Unconsolidated Joint Ventures
OPERATING RESULTS
Revenue											88,762
Expenses
Other operating expenses											34,607
Impairment loss											38,465	[1]
Depreciation and amortization											29,012
Interest expense											29,835
Total expenses											131,919
Net loss											(43,157)
Our share of net loss											$ (4,406)	[2]

[1] The venture recorded an impairment loss on the real estate property on the venture's financial statements during the year ended December 31, 2010. During 2008, we recorded an impairment of our equity method investment in the Fireman's Fund Headquarters real estate venture, as we determined that during 2008 the fair value of our equity method investment in the Fireman's Fund Headquarters was below our historical cost as a result of a reduction in real estate values due to the credit crisis that occurred during 2008. As a result, for the year ended December 31, 2010, we did not record our share of the impairment losses recorded on the venture's financial statements, as we believe our investment in the Fireman's Fund Headquarters joint venture at December 31, 2010 (adjusted for previously recorded impairment losses) was not impaired.

[2] Excludes the gain recorded on the acquisition of The Landmark at One Market of $4,297.