Condensed consolidating financial information Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues:
Rental	$ 151,805			$ 134,992	$ 295,413	$ 265,562
Tenant recoveries	49,594			40,944	97,988	82,626
Other income	2,757			466	7,508	4,400
Total revenues	204,156			176,402	400,909	352,588
Expenses:
Rental operations	62,250			52,353	123,473	104,860
General and administrative	14,989			13,836	29,376	27,060
Interest	26,668			17,433	49,904	36,556
Depreciation and amortization	62,171			57,314	121,091	107,735
Impairment of real estate	0		$ 16,600	0	14,510	0
Loss on early extinguishment of debt	189			0	189	0
Total expenses	166,267			140,936	338,543	276,211
Equity in earnings of unconsolidated joint ventures	541			0	1,115	0
Income (Loss) from Subsidiaries, before Tax	0			0	0	0
Income from continuing operations	38,430			35,466	63,481	76,377
(Loss) income from discontinued operations, net	0			(147)	(43)	(309)
Gain on sales of real estate – land parcels	0			797	0	797
Net income	38,430			36,116	63,438	76,865
Dividends on preferred stock	(6,246)			(6,472)	(12,493)	(12,943)
Net income attributable to noncontrolling interests	(263)			(1,307)	(755)	(2,502)
Net income attributable to unvested restricted stock awards	(630)			(405)	(1,113)	(779)
Net income attributable to Alexandria’s common stockholders	31,291			27,932	49,077	60,641
Alexandria Real Estate Equities, Inc. (Issuer)
Revenues:
Rental	0			0	0	0
Tenant recoveries	0			0	0	0
Other income	3,509			2,916	6,535	5,835
Total revenues	3,509			2,916	6,535	5,835
Expenses:
Rental operations	0			0	0	0
General and administrative	13,223			11,506	25,449	22,366
Interest	19,867			12,493	37,024	26,032
Depreciation and amortization	1,469			1,456	2,716	2,927
Impairment of real estate	0				0
Loss on early extinguishment of debt	189				189
Total expenses	34,748			25,455	65,378	51,325
Equity in earnings of unconsolidated joint ventures	0				0
Income (Loss) from Subsidiaries, before Tax	69,406			57,355	121,526	119,860
Income from continuing operations				34,816	62,683	74,370
(Loss) income from discontinued operations, net				(7)	0	(7)
Gain on sales of real estate – land parcels				0		0
Net income	38,167			34,809	62,683	74,363
Dividends on preferred stock	(6,246)			(6,472)	(12,493)	(12,943)
Net income attributable to noncontrolling interests	0			0	0	0
Net income attributable to unvested restricted stock awards	(630)			(405)	(1,113)	(779)
Net income attributable to Alexandria’s common stockholders	31,291			27,932	49,077	60,641
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Revenues:
Rental	0			0	0	0
Tenant recoveries	0			0	0	0
Other income	0			(1,535)	(41)	(1,535)
Total revenues	0			(1,535)	(41)	(1,535)
Expenses:
Rental operations	0			0	0	0
General and administrative	0			0	0	0
Interest	0			0	0	0
Depreciation and amortization	0			0	0	0
Impairment of real estate	0				0
Loss on early extinguishment of debt	0	$ 0			0
Total expenses	0			0	0	0
Equity in earnings of unconsolidated joint ventures	0				0
Income (Loss) from Subsidiaries, before Tax	65,246			56,302	110,836	114,608
Income from continuing operations				54,767	110,795	113,073
(Loss) income from discontinued operations, net				0	0	0
Gain on sales of real estate – land parcels				0		0
Net income	65,246			54,767	110,795	113,073
Dividends on preferred stock	0			0	0	0
Net income attributable to noncontrolling interests	0			0	0	0
Net income attributable to unvested restricted stock awards	0			0	0	0
Net income attributable to Alexandria’s common stockholders	65,246			54,767	110,795	113,073
Combined Non- Guarantor Subsidiaries
Revenues:
Rental	151,805			134,992	295,413	265,562
Tenant recoveries	49,594			40,944	97,988	82,626
Other income	3,425			2,532	8,989	7,165
Total revenues	204,824			178,468	402,390	355,353
Expenses:
Rental operations	62,250			52,353	123,473	104,860
General and administrative	5,943			5,777	11,902	11,759
Interest	6,801			4,940	12,880	10,524
Depreciation and amortization	60,702			55,858	118,375	104,808
Impairment of real estate	0				14,510
Loss on early extinguishment of debt	0	$ 0			0
Total expenses	135,696			118,928	281,140	231,951
Equity in earnings of unconsolidated joint ventures	541				1,115
Income (Loss) from Subsidiaries, before Tax	1,270			1,081	2,187	2,229
Income from continuing operations				60,621	124,552	125,631
(Loss) income from discontinued operations, net				(140)	(43)	(302)
Gain on sales of real estate – land parcels				797		797
Net income	70,939			61,278	124,509	126,126
Dividends on preferred stock	0			0	0	0
Net income attributable to noncontrolling interests	(263)			(1,307)	(755)	(2,502)
Net income attributable to unvested restricted stock awards	0			0	0	0
Net income attributable to Alexandria’s common stockholders	70,676			59,971	123,754	123,624
Eliminations
Revenues:
Rental	0			0	0	0
Tenant recoveries	0			0	0	0
Other income	(4,177)			(3,447)	(7,975)	(7,065)
Total revenues	(4,177)			(3,447)	(7,975)	(7,065)
Expenses:
Rental operations	0			0	0	0
General and administrative	(4,177)			(3,447)	(7,975)	(7,065)
Interest	0			0	0	0
Depreciation and amortization	0			0	0	0
Impairment of real estate	0				0
Loss on early extinguishment of debt	0				0
Total expenses	(4,177)			(3,447)	(7,975)	(7,065)
Equity in earnings of unconsolidated joint ventures	0				0
Income (Loss) from Subsidiaries, before Tax	(135,922)			(114,738)	(234,549)	(236,697)
Income from continuing operations				(114,738)	(234,549)	(236,697)
(Loss) income from discontinued operations, net				0	0	0
Gain on sales of real estate – land parcels				0		0
Net income	(135,922)			(114,738)	(234,549)	(236,697)
Dividends on preferred stock	0			0	0	0
Net income attributable to noncontrolling interests	0			0	0	0
Net income attributable to unvested restricted stock awards	0			0	0	0
Net income attributable to Alexandria’s common stockholders	$ (135,922)			$ (114,738)	$ (234,549)	$ (236,697)