Segments - Property Expenses of Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Rental expenses	$ 3,976	$ 3,229
Real estate taxes	1,343	1,212
Property expenses	5,319	4,441
Office Real Estate [Member]
Segment Reporting Information [Line Items]
Rental expenses	1,587	1,405
Real estate taxes	544	541
Retail Real Estate [Member]
Segment Reporting Information [Line Items]
Rental expenses	1,322	1,220
Real estate taxes	503	460
Multifamily Residential Real Estate [Member]
Segment Reporting Information [Line Items]
Rental expenses	1,067	604
Real estate taxes	$ 296	$ 211

Other operating costs incurred during the reporting period and may include amounts paid to maintain the property.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.2)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_CostOfOtherPropertyOperatingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense incurred and directly related to generating revenue from leased and rented property or equipment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.2(c))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A tax based on the assessed value of real estate by the local government. The tax is usually based on the value of property (including the land).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 30

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6419918&loc=d3e35301-107843

+ Details

Name:	us-gaap_RealEstateTaxExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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