Condensed consolidating financial information Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income	$ (108,116)	$ 38,430	$ (98,150)	$ 63,438
Unrealized gains on available-for-sale equity securities:
Unrealized holding gains arising during the period	15,989	55,401	(31,434)	83,836
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	(3,061)	1,362	(10,087)	2,465
Unrealized gains (losses) on available-for-sale equity securities, net	12,928	56,763	(41,521)	86,301
Unrealized losses on interest rate hedge agreements:
Unrealized interest rate hedge losses arising during the period	(3,676)	(1,225)	(10,637)	(4,238)
Reclassification adjustment for amortization of interest expense included in net income	1,865	710	2,023	1,215
Unrealized gains on interest rate swap agreements, net	(1,811)	(515)	(8,614)	(3,023)
Unrealized foreign currency translation (losses) gains arising during the period	(1,364)	(1,507)	2,164	(7,778)
Reclassification adjustment for losses included in net income	7,028	0	7,028	9,236
Unrealized foreign currency translation (losses) gains arising during the period	5,664	(1,507)	9,192	1,458
Total other comprehensive income (loss)	16,781	54,741	(40,943)	84,736
Comprehensive income	(91,335)	93,171	(139,093)	148,174
Less: comprehensive income attributable to noncontrolling interests	(3,476)	(237)	(7,506)	(883)
Comprehensive (loss) income attributable to Alexandria Real Estate Equities, Inc.’s stockholders	(94,811)	92,934	(146,599)	147,291
Eliminations
Net income	171,692	(135,922)	102,359	(234,549)
Unrealized gains on available-for-sale equity securities:
Unrealized holding gains arising during the period	0	0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	0	0	0	0
Unrealized gains (losses) on available-for-sale equity securities, net	0	0	0	0
Unrealized losses on interest rate hedge agreements:
Unrealized interest rate hedge losses arising during the period	0	0	0	0
Reclassification adjustment for amortization of interest expense included in net income	0	0	0	0
Unrealized gains on interest rate swap agreements, net	0	0	0	0
Unrealized foreign currency translation (losses) gains arising during the period	0	0	0	0
Reclassification adjustment for losses included in net income	0		0	0
Unrealized foreign currency translation (losses) gains arising during the period	0	0	0	0
Total other comprehensive income (loss)	0	0	0	0
Comprehensive income	171,692	(135,922)	102,359	(234,549)
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to Alexandria Real Estate Equities, Inc.’s stockholders	171,692	(135,922)	102,359	(234,549)
Alexandria Real Estate Equities, Inc. (Issuer)
Net income	(111,616)	38,167	(105,680)	62,683
Unrealized gains on available-for-sale equity securities:
Unrealized holding gains arising during the period	0	0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	0	0	0	0
Unrealized gains (losses) on available-for-sale equity securities, net	0	0	0	0
Unrealized losses on interest rate hedge agreements:
Unrealized interest rate hedge losses arising during the period	(3,676)	(1,225)	(10,637)	(4,238)
Reclassification adjustment for amortization of interest expense included in net income	1,865	710	2,023	1,215
Unrealized gains on interest rate swap agreements, net	(1,811)	(515)	(8,614)	(3,023)
Unrealized foreign currency translation (losses) gains arising during the period	0	0	0	0
Reclassification adjustment for losses included in net income	0		0	0
Unrealized foreign currency translation (losses) gains arising during the period	0	0	0	0
Total other comprehensive income (loss)	(1,811)	(515)	(8,614)	(3,023)
Comprehensive income	(113,427)	37,652	(114,294)	59,660
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to Alexandria Real Estate Equities, Inc.’s stockholders	(113,427)	37,652	(114,294)	59,660
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Net income	(92,465)	65,246	(61,790)	110,795
Unrealized gains on available-for-sale equity securities:
Unrealized holding gains arising during the period	101	76	78	22
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	0	0	11	41
Unrealized gains (losses) on available-for-sale equity securities, net	101	76	89	63
Unrealized losses on interest rate hedge agreements:
Unrealized interest rate hedge losses arising during the period	0	0	0	0
Reclassification adjustment for amortization of interest expense included in net income	0	0	0	0
Unrealized gains on interest rate swap agreements, net	0	0	0	0
Unrealized foreign currency translation (losses) gains arising during the period	0	0	0	0
Reclassification adjustment for losses included in net income	0		0	0
Unrealized foreign currency translation (losses) gains arising during the period	0	0	0	0
Total other comprehensive income (loss)	101	76	89	63
Comprehensive income	(92,364)	65,322	(61,701)	110,858
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to Alexandria Real Estate Equities, Inc.’s stockholders	(92,364)	65,322	(61,701)	110,858
Combined Non- Guarantor Subsidiaries
Net income	(75,727)	70,939	(33,039)	124,509
Unrealized gains on available-for-sale equity securities:
Unrealized holding gains arising during the period	15,888	55,325	(31,512)	83,814
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	(3,061)	1,362	(10,098)	2,424
Unrealized gains (losses) on available-for-sale equity securities, net	12,827	56,687	(41,610)	86,238
Unrealized losses on interest rate hedge agreements:
Unrealized interest rate hedge losses arising during the period	0	0	0	0
Reclassification adjustment for amortization of interest expense included in net income	0	0	0	0
Unrealized gains on interest rate swap agreements, net	0	0	0	0
Unrealized foreign currency translation (losses) gains arising during the period	(1,364)	(1,507)	2,164	(7,778)
Reclassification adjustment for losses included in net income	7,028		7,028	9,236
Unrealized foreign currency translation (losses) gains arising during the period	5,664	(1,507)	9,192	1,458
Total other comprehensive income (loss)	18,491	55,180	(32,418)	87,696
Comprehensive income	(57,236)	126,119	(65,457)	212,205
Less: comprehensive income attributable to noncontrolling interests	(3,476)	(237)	(7,506)	(883)
Comprehensive (loss) income attributable to Alexandria Real Estate Equities, Inc.’s stockholders	$ (60,712)	$ 125,882	$ (72,963)	$ 211,322