Changes in Accumulated Depreciation Including Real Estate Assets Held for Sale (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Real Estate and Accumulated Depreciation [Line Items]
Real estate held for sale	$ 68,148	$ 109,173
Intangible lease assets held for sale	2,194	3,555
Accumulated depreciation of real estate held for sale	8,964	10,910
Accumulated amortization of intangible lease assets	$ 1,585	$ 1,941

The cumulative amount of depreciation for real estate property held for investment purposes.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(3))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 7

Name:	us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant