Quarterly financial data (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended															12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012	Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenues (1)	$ 168,823	[1]	$ 158,315	[1]	$ 153,930	[1]	$ 150,083	[1]	$ 151,254	$ 142,547	[1]	$ 145,296	[1]	$ 135,400	[1]	$ 631,151	$ 574,497	$ 536,780
Net income attributable to Alexandria Real Estate Equities, Inc.’s common stockholders	$ 36,247		$ 24,579		$ 25,483		$ 22,442		$ 21,000	$ 10,646		$ 17,616		$ 18,368		$ 108,751	$ 67,630	$ 101,973
Earnings per share attributable to Alexandria’s common stockholders – basic and diluted:
Basic and diluted (2)	$ 0.51	[2]	$ 0.35	[2]	$ 0.38	[2]	$ 0.36	[2]	$ 0.33	$ 0.17	[2]	$ 0.29	[2]	$ 0.30	[2]	$ 1.60	$ 1.09	$ 1.73

[1] All periods have been adjusted from amounts previously disclosed in our quarterly filings on Form 10-Q to reclassify amounts related to discontinued operations. See Note 17, Discontinued Operations.

[2] Quarterly earnings per common share amounts may not total to the annual amounts due to rounding and due to the increase in the weighted average shares of common stock outstanding.