Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Income Statements
Revenues	$ 408,114	$ 390,484	$ 373,856	$ 358,842	$ 340,463	$ 341,823	$ 325,034	$ 320,139	$ 1,531,296	$ 1,327,459	$ 1,128,097
Expenses:
Rental operations									445,492	381,120	325,609
General and administrative									108,823	90,405	75,009
Interest									173,675	157,495	128,645
Depreciation and amortization									544,612	477,661	416,783
Impairment of real estate									12,334	6,311	203
Loss on early extinguishment of debt									47,570	1,122	3,451
Total expenses									1,332,506	1,114,114	949,700
Equity in earnings (losses) of unconsolidated real estate joint ventures									10,136	43,981	15,426
Equity in earnings of affiliates									0	0	0
Investment income									194,647	136,763	0
Gain on sales of real estate – rental properties									474	8,704	270
Gain on sales of real estate - land parcels									0	0	111
Net income (loss)									404,047	402,793	194,204
Net income attributable to noncontrolling interest									(40,882)	(23,481)	(25,111)
Net income (loss) attributable to Alexandria Real Estate Equities, Inc.'s stockholders									363,165	379,312	169,093
Dividends on preferred stock									(3,204)	(5,060)	(7,666)
Preferred stock redemption charge									(2,580)	(4,240)	(11,279)
Net income attributable to unvested restricted stock awards									(6,386)	(6,029)	(4,753)
Net Income attributable to Alexandria Real Estate Equities, Inc.'s common stockholders									350,995	363,983	145,395
Eliminations
Condensed Income Statements
Revenues									(22,983)	(21,538)	(18,169)
Expenses:
Rental operations									0	0	0
General and administrative									(22,983)	(21,538)	(18,169)
Interest									0	0	0
Depreciation and amortization									0	0	0
Impairment of real estate									0	0	0
Loss on early extinguishment of debt									0	0	0
Total expenses									(22,983)	(21,538)	(18,169)
Equity in earnings (losses) of unconsolidated real estate joint ventures									0	0	0
Equity in earnings of affiliates									(1,158,401)	(1,056,573)	(672,537)
Investment income									0	0
Gain on sales of real estate – rental properties									0	0	0
Gain on sales of real estate - land parcels											0
Net income (loss)									(1,158,401)	(1,056,573)	(672,537)
Net income attributable to noncontrolling interest									0	0	0
Net income (loss) attributable to Alexandria Real Estate Equities, Inc.'s stockholders									(1,158,401)	(1,056,573)	(672,537)
Dividends on preferred stock									0	0	0
Preferred stock redemption charge									0	0	0
Net income attributable to unvested restricted stock awards									0	0	0
Net Income attributable to Alexandria Real Estate Equities, Inc.'s common stockholders									(1,158,401)	(1,056,573)	(672,537)
Alexandria Real Estate Equities, Inc. (Issuer)
Condensed Income Statements
Revenues									22,731	19,275	15,238
Expenses:
Rental operations									0	0	0
General and administrative									106,523	88,707	73,897
Interest									164,249	136,036	101,876
Depreciation and amortization									6,949	6,339	7,625
Impairment of real estate									0	0	0
Loss on early extinguishment of debt									40,209	823	670
Total expenses									317,930	231,905	184,068
Equity in earnings (losses) of unconsolidated real estate joint ventures									0	0	0
Equity in earnings of affiliates									658,364	591,942	337,923
Investment income									0	0
Gain on sales of real estate – rental properties									0	0	0
Gain on sales of real estate - land parcels											0
Net income (loss)									363,165	379,312	169,093
Net income attributable to noncontrolling interest									0	0	0
Net income (loss) attributable to Alexandria Real Estate Equities, Inc.'s stockholders									363,165	379,312	169,093
Dividends on preferred stock									(3,204)	(5,060)	(7,666)
Preferred stock redemption charge									(2,580)	(4,240)	(11,279)
Net income attributable to unvested restricted stock awards									(6,386)	(6,029)	(4,753)
Net Income attributable to Alexandria Real Estate Equities, Inc.'s common stockholders									350,995	363,983	145,395
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Condensed Income Statements
Revenues									0	0	(2,575)
Expenses:
Rental operations									0	0	0
General and administrative									0	0	0
Interest									0	0	0
Depreciation and amortization									0	0	0
Impairment of real estate									0	0	0
Loss on early extinguishment of debt									0	0	0
Total expenses									0	0	0
Equity in earnings (losses) of unconsolidated real estate joint ventures									0	0	0
Equity in earnings of affiliates									490,393	455,574	328,230
Investment income									34	528
Gain on sales of real estate – rental properties									0	0	0
Gain on sales of real estate - land parcels											0
Net income (loss)									490,427	456,102	325,655
Net income attributable to noncontrolling interest									0	0	0
Net income (loss) attributable to Alexandria Real Estate Equities, Inc.'s stockholders									490,427	456,102	325,655
Dividends on preferred stock									0	0	0
Preferred stock redemption charge									0	0	0
Net income attributable to unvested restricted stock awards									0	0	0
Net Income attributable to Alexandria Real Estate Equities, Inc.'s common stockholders									490,427	456,102	325,655
Combined Non- Guarantor Subsidiaries
Condensed Income Statements
Revenues									1,531,548	1,329,722	1,133,603
Expenses:
Rental operations									445,492	381,120	325,609
General and administrative									25,283	23,236	19,281
Interest									9,426	21,459	26,769
Depreciation and amortization									537,663	471,322	409,158
Impairment of real estate									12,334	6,311	203
Loss on early extinguishment of debt									7,361	299	2,781
Total expenses									1,037,559	903,747	783,801
Equity in earnings (losses) of unconsolidated real estate joint ventures									10,136	43,981	15,426
Equity in earnings of affiliates									9,644	9,057	6,384
Investment income									194,613	136,235
Gain on sales of real estate – rental properties									474	8,704	270
Gain on sales of real estate - land parcels											111
Net income (loss)									708,856	623,952	371,993
Net income attributable to noncontrolling interest									(40,882)	(23,481)	(25,111)
Net income (loss) attributable to Alexandria Real Estate Equities, Inc.'s stockholders									667,974	600,471	346,882
Dividends on preferred stock									0	0	0
Preferred stock redemption charge									0	0	0
Net income attributable to unvested restricted stock awards									0	0	0
Net Income attributable to Alexandria Real Estate Equities, Inc.'s common stockholders									667,974	600,471	346,882
Income from rentals
Condensed Income Statements
Revenues									1,516,864	1,314,781	1,122,325
Income from rentals | Eliminations
Condensed Income Statements
Revenues									0	0	0
Income from rentals | Alexandria Real Estate Equities, Inc. (Issuer)
Condensed Income Statements
Revenues									0	0	0
Income from rentals | Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Condensed Income Statements
Revenues									0	0	0
Income from rentals | Combined Non- Guarantor Subsidiaries
Condensed Income Statements
Revenues									1,516,864	1,314,781	1,122,325
Other income
Condensed Income Statements
Revenues									14,432	12,678	5,772
Other income | Eliminations
Condensed Income Statements
Revenues									(22,983)	(21,538)	(18,169)
Other income | Alexandria Real Estate Equities, Inc. (Issuer)
Condensed Income Statements
Revenues									22,731	19,275	15,238
Other income | Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Condensed Income Statements
Revenues									0	0	(2,575)
Other income | Combined Non- Guarantor Subsidiaries
Condensed Income Statements
Revenues									$ 14,684	$ 14,941	$ 11,278