Condensed Consolidated Statements of Comprehensive Income (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	$ 18,305	$ 32,995	$ 76,721	$ 99,931
Unrealized losses on marketable securities:
Unrealized holding gains (losses) arising during the period	796	(669)	1,363	(657)
Reclassification adjustment for gains included in net income	(1,421)	(1,947)	(2,107)	(1,947)
Unrealized losses on marketable securities, net	(625)	(2,616)	(744)	(2,604)
Unrealized gains on interest rate swaps:
Unrealized interest rate swap losses arising during the period	(2,818)	(2,822)	(9,982)	(8,077)
Reclassification adjustment for amortization of interest expense included in net income	5,956	5,381	17,626	16,121
Unrealized gains on interest rate swap agreements, net	3,138	2,559	7,644	8,044
Foreign currency translation gains (losses)	15,104	(25,814)	7,871	(19,255)
Total other comprehensive income (loss)	17,617	(25,871)	14,771	(13,815)
Comprehensive income	35,922	7,124	91,492	86,116
Less: comprehensive income attributable to noncontrolling interests	(805)	(1,024)	(2,379)	(2,885)
Comprehensive income attributable to Alexandria Real Estate Equities, Inc.'s common stockholders	$ 35,117	$ 6,100	$ 89,113	$ 83,231