The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Investments in Unconsolidated Entities (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended			0 Months Ended	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Dec. 20, 2012 8 Spruce Street [Member]	Jan. 31, 2013 8 Spruce Street [Member]	Dec. 18, 2012 8 Spruce Street [Member]
Significant Acquisitions and Disposals [Line Items]
Company's partner, ownership percentage				49.00%
Portion of equity ownership, cash sales price				$ 250,390
Equity ownership interests, ownership percentage				18.00%		36.00%
Equity ownership interests, net cash proceeds				129,037
Gain on disposition of partial interest in a rental property	$ 0	$ 17,665	$ 257,990		$ 34,959