Condensed Consolidating Financials - Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets
Investments in real estate	$ 12,872,824		$ 11,913,693
Investments in and advances to affiliates	334,162		237,507
Cash and cash equivalents	198,909		234,181
Restricted cash	39,316		37,949
Tenant receivables	9,228		9,798
Deferred rent	585,082		530,237
Deferred leasing costs	247,468		239,070
Investments	1,057,854		892,264
Investments in and advances to affiliates	0		0
Other assets	694,627		370,257
Total assets	16,039,470		14,464,956
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	354,186		630,547
Unsecured senior notes payable	5,140,914		4,292,293
Unsecured senior line of credit	514,000		208,000
Unsecured senior bank term loan	347,105		347,415
Accounts payable, accrued expenses, and tenant security deposits	1,157,417		981,707
Dividends payable	114,379		110,280
Total liabilities	7,628,001		6,570,242
Redeemable noncontrolling interests	10,994		10,786
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	7,629,020		7,341,965
Noncontrolling interests	771,455		541,963
Total equity	8,400,475	$ 8,344,025	7,883,928	$ 6,989,274	$ 6,723,135	$ 6,471,660
Total liabilities, noncontrolling interests, and equity	16,039,470		14,464,956
Eliminations
Assets
Investments in real estate	0		0
Investments in and advances to affiliates	0		0
Cash and cash equivalents	0		0
Restricted cash	0		0
Tenant receivables	0		0
Deferred rent	0		0
Deferred leasing costs	0		0
Investments	0		0
Investments in and advances to affiliates	(26,230,542)		(23,408,191)
Other assets	0		0
Total assets	(26,230,542)		(23,408,191)
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0		0
Unsecured senior notes payable	0		0
Unsecured senior line of credit	0		0
Unsecured senior bank term loan	0		0
Accounts payable, accrued expenses, and tenant security deposits	0		0
Dividends payable	0		0
Total liabilities	0		0
Redeemable noncontrolling interests	0		0
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	(26,230,542)		(23,408,191)
Noncontrolling interests	0		0
Total equity	(26,230,542)		(23,408,191)
Total liabilities, noncontrolling interests, and equity	(26,230,542)		(23,408,191)
Alexandria Real Estate Equities, Inc. (Issuer)
Assets
Investments in real estate	0		0
Investments in and advances to affiliates	0		0
Cash and cash equivalents	89,615		119,112
Restricted cash	194		193
Tenant receivables	0		0
Deferred rent	0		0
Deferred leasing costs	0		0
Investments	0		0
Investments in and advances to affiliates	13,719,957		12,235,577
Other assets	55,481		56,353
Total assets	13,865,247		12,411,235
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0		0
Unsecured senior notes payable	5,140,914		4,292,293
Unsecured senior line of credit	514,000		208,000
Unsecured senior bank term loan	347,105		347,415
Accounts payable, accrued expenses, and tenant security deposits	119,829		111,282
Dividends payable	114,379		110,280
Total liabilities	6,236,227		5,069,270
Redeemable noncontrolling interests	0		0
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	7,629,020		7,341,965
Noncontrolling interests	0		0
Total equity	7,629,020		7,341,965
Total liabilities, noncontrolling interests, and equity	13,865,247		12,411,235
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Assets
Investments in real estate	0		0
Investments in and advances to affiliates	0		0
Cash and cash equivalents	0		0
Restricted cash	0		0
Tenant receivables	0		0
Deferred rent	0		0
Deferred leasing costs	0		0
Investments	1,203		1,262
Investments in and advances to affiliates	12,260,877		10,949,631
Other assets	0		0
Total assets	12,262,080		10,950,893
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	0		0
Unsecured senior notes payable	0		0
Unsecured senior line of credit	0		0
Unsecured senior bank term loan	0		0
Accounts payable, accrued expenses, and tenant security deposits	0		0
Dividends payable	0		0
Total liabilities	0		0
Redeemable noncontrolling interests	0		0
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	12,262,080		10,950,893
Noncontrolling interests	0		0
Total equity	12,262,080		10,950,893
Total liabilities, noncontrolling interests, and equity	12,262,080		10,950,893
Combined Non- Guarantor Subsidiaries
Assets
Investments in real estate	12,872,824		11,913,693
Investments in and advances to affiliates	334,162		237,507
Cash and cash equivalents	109,294		115,069
Restricted cash	39,122		37,756
Tenant receivables	9,228		9,798
Deferred rent	585,082		530,237
Deferred leasing costs	247,468		239,070
Investments	1,056,651		891,002
Investments in and advances to affiliates	249,708		222,983
Other assets	639,146		313,904
Total assets	16,142,685		14,511,019
Liabilities, Noncontrolling Interests, and Equity
Secured notes payable	354,186		630,547
Unsecured senior notes payable	0		0
Unsecured senior line of credit	0		0
Unsecured senior bank term loan	0		0
Accounts payable, accrued expenses, and tenant security deposits	1,037,588		870,425
Dividends payable	0		0
Total liabilities	1,391,774		1,500,972
Redeemable noncontrolling interests	10,994		10,786
Alexandria Real Estate Equities, Inc.’s stockholders’ equity	13,968,462		12,457,298
Noncontrolling interests	771,455		541,963
Total equity	14,739,917		12,999,261
Total liabilities, noncontrolling interests, and equity	$ 16,142,685		$ 14,511,019