Net income attributable to Alexandria Real Estate Equities, Inc. (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income attributable to Alexandria Real Estate Equities, Inc.:
Income from continuing operations	$ 24,086	$ 31,144	$ 74,621	$ 92,006
Gain on sale of land parcel		46	1,864	46
Less: net income attributable to noncontrolling interests	(828)	(966)	(2,390)	(2,833)
Income from continuing operations attributable to Alexandria Real Estate Equities, Inc.	23,258	30,224	74,095	89,219
(Loss) income from discontinued operations:
Income from discontinued operations before impairment of real estate	4,018	2,799	10,035	8,873
Impairment of real estate	(9,799)	(994)	(9,799)	(994)
(Loss) income from discontinued operations, net	(5,781)	1,805	236	7,879
Net income attributable to Alexandria Real Estate Equities, Inc.	$ 17,477	$ 33,029	$ 74,331	$ 97,098