Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-URI http://asc.fasb.org/subtopic&trid=2155824

Name:	us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Basis of Presentation and Summary of Significant Accounting Policies - Real Estate Investments (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives		39 years
Site Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives		15 years
Site Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives		25 years
Tenant Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives		Shorter of the useful lives or the terms of the related leases