Noncontrolling interests (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Apr. 01, 2015 USD ($)	Jun. 30, 2016 USD ($) ft² property	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) ft² property	Jun. 30, 2015 USD ($)	Mar. 31, 2015
Noncontrolling interests
Income (Loss) from Continuing Operations Attributable to Parent		$ (111,616)	$ 38,167	$ (105,680)	$ 62,726
(Loss) income from discontinued operations, net		0	0	0	(43)
Payable for purchase of noncontrolling interest				0	52,672
Net (loss) income attributable to Alexandria Real Estate Equities, Inc.’s stockholders		$ (111,616)	38,167	$ (105,680)	$ 62,683
Noncontrolling Interests
Noncontrolling interests
Number of projects subject to ownership from noncontrolling interests | property		9		9
Noncontrolling Interest, Increase from Sale of Parent Equity Interest				$ 30,950
Alexandria Technology Square [Member]
Noncontrolling interests
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners						10.00%
Payable for purchase of noncontrolling interest	$ 54,300		$ 108,300	$ 54,000
Alexandria Technology Square [Member]
Noncontrolling interests
Area of Real Estate Property | ft²		1,200,000		1,200,000
ACLS at Campus Pointe [Member] | 10290 Campus Point Drive [Member]
Noncontrolling interests
Area of Real Estate Property | ft²		304,326		304,326
Noncontrolling Interest, Increase from Sale of Parent Equity Interest				$ 30,736
Noncontrolling Interest - Historical Cost Basis		$ 30,900		$ 30,900