Total expenditures for additions to long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets of the reportable segment; if the amount: (a) is included in the determination of segment assets reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in the determination of segment assets.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 28

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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Amount of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 42

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

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

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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The number of units in a real estate property owned as of the balance sheet date.

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Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

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Business Segments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Segment	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Number of reportable segments	2
Revenues in continuing operations from government subsidies	$ 97.9	$ 90.8	$ 85.4
AIMCO PROPERTIES, L.P
Segment Reporting Information [Line Items]
Interest income recognized from notes receivable from Aimco		1.3	0.9
Conventional Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Capital additions related to segments	252.3	191.6	140.1
Affordable Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Capital additions related to segments	$ 19.8	$ 15.6	$ 35.2
Affordable Real Estate [Member]
Segment Reporting Information [Line Items]
Number of owned real estate properties in segments	90
Number of units in owned real estate properties in segments	12,098
Conventional Real Estate [Member]
Segment Reporting Information [Line Items]
Number of owned real estate properties in segments	175
Number of units in owned real estate properties in segments	55,879