This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References+ Details

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, and noncontrolling interest.

+ References+ Details

- Definition

This element represents the overall income (loss) from a disposal group that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items before deduction or consideration of the amount which may be allocable to noncontrolling interests, if any. Includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Basis of presentation (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Net income attributable to Alexandria Real Estate Equities, Inc.:
Income (loss) from continuing operations	$ 34,349	$ (12,164)	$ 67,033	$ 16,028
(Loss) Income from discontinued operations, net	(38)	(60)	(97)	533
Net income attributable to Alexandria Real Estate Equities, Inc.	34,311	(12,224)	66,936	16,561
Number of forms of stock-based compensation under the equity incentive plan	2		2
Assets:
"Available for sale" securities	8,559		8,559		8,033
Liabilities:
Interest rate hedge agreements	39,221		39,221		44,645
Fair value measured on recurring basis \| Fair Value
Assets:
"Available for sale" securities	8,559		8,559		8,033
Liabilities:
Interest rate hedge agreements	39,221		39,221		44,645
Fair value measured on recurring basis \| Quoted Prices in Active Markets for Identical Assets and Liabilities
Assets:
"Available for sale" securities	8,559		8,559		8,033
Fair value measured on recurring basis \| "Significant Other Observable Inputs"
Liabilities:
Interest rate hedge agreements	$ 39,221		$ 39,221		$ 44,645