Statements of Cash Flows (Parenthetical) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Statement of Cash Flows [Abstract]
Receivable on previously capitalized real estate taxes on Anacostia property	$ 41	$ 2,250

Amount of significant noncash items other than depreciation, depletion, and amortization expense attributed to a reportable segment.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph j

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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