Investments in Unconsolidated Ventures (Details)	3 Months Ended
Dec. 31, 2016 USD ($) property investment	Dec. 31, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of investments \| investment	2
Contributions of unconsolidated joint ventures \| $	$ 14,335,000	$ 0
Number of properties \| property	30
Joint Venture, Thirty Two Percent Ownership
Schedule of Equity Method Investments [Line Items]
Contributions of unconsolidated joint ventures \| $	$ 5,670,000
Joint ventures ownership percentage	32.00%
Number of properties \| property	374
Joint Venture, Forty Six Percent Ownership
Schedule of Equity Method Investments [Line Items]
Contributions of unconsolidated joint ventures \| $	$ 8,665,000
Joint ventures ownership percentage	46.00%
Number of real estate properties, to be constructed \| property	339

Equity Method Investments, Number of Investments

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- Definition

Number Of Real Estate Properties, To Be Constructed

+ References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: 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=66011266&loc=d3e33918-111571

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- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

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- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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