Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities
Net income (loss)	$ 404,047	$ 402,793	$ 194,204
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	544,612	477,661	416,783
Loss on early extinguishment of debt	47,570	1,122	3,451
Impairment of real estate	12,334	6,311	203
Gain on sales of real estate – rental properties	(474)	(8,704)	(270)
Gain on sales of real estate - land parcels	0	0	(111)
Equity in earnings of unconsolidated real estate joint ventures	(10,136)	(43,981)	(15,426)
Distributions of earnings from unconsolidated real estate joint ventures	2,796	430	1,618
Amortization of loan fees	9,105	10,271	11,149
Amortization of debt discount (premiums)	(3,777)	(2,406)	(2,512)
Amortization of acquired below-market leases	(29,813)	(21,938)	(19,055)
Deferred rent	(104,235)	(93,883)	(107,643)
Stock compensation expense	43,640	35,019	25,610
Equity in earnings of affiliates	0	0	0
Investment income	(194,647)	(136,763)	(1,329)
Changes in operating assets and liabilities:
Tenant receivables	(897)	435	(502)
Deferred leasing costs	(54,455)	(57,088)	(62,639)
Other assets	(20,825)	(20,849)	(18,222)
Accounts payable, accrued expenses, and tenant security deposits	39,012	21,909	25,573
Net cash provided by operating activities	683,857	570,339	450,882
Investing Activities
Proceeds from sales of real estate	6,619	20,190	15,432
Additions to real estate	(1,224,541)	(927,168)	(893,685)
Purchase of real estate	(2,259,778)	(1,037,180)	(675,584)
Deposits for investing activities	(18,107)	(2,000)	(2,300)
Investments in subsidiaries	0	0	0
Acquisition of interest in unconsolidated real estate joint venture	0	(35,922)	(60,291)
Investments in unconsolidated real estate joint venture	(102,081)	(116,008)	(17,876)
Return of capital from unconsolidated real estate joint ventures	14	68,592	38,576
Additions to investments	(190,778)	(235,943)	(171,881)
Sales of investments	147,332	103,679	30,483
Net cash used in investing activities	(3,641,320)	(2,161,760)	(1,737,126)
Financing Activities
Borrowings from secured notes payable	0	17,784	153,405
Repayments of borrowings from secured notes payable	(306,199)	(156,888)	(396,240)
Proceeds from issuance of unsecured senior notes payable	2,721,169	899,321	1,023,262
Repayments of unsecured senior notes payable	(950,000)	0	0
Borrowings from unsecured senior line of credit	5,056,000	4,741,000	3,858,000
Repayments of borrowings from unsecured senior line of credit	(4,880,000)	(4,583,000)	(3,836,000)
Proceeds from issuance of commercial paper program	2,233,000	0	0
Repayments of borrowings from commercial paper program	(2,233,000)	0	0
Repayment of unsecured senior bank term loan	(350,000)	(200,000)	(200,000)
Premium paid for early extinguishment of debt	(41,351)	0
Transfers to/from parent company	0	0	0
Payment of loan fees	(27,182)	(19,292)	(10,019)
Taxes paid related to net settlement of equity awards	(25,477)	0	0
Repurchase of 7.00% Series D convertible preferred stock	(9,240)	(13,976)	(17,934)
Redemption of 6.45% Series E redeemable preferred stock	0	0	(130,350)
Proceeds from the issuance of common stock	1,216,445	1,293,301	1,275,397
Dividends paid on common stock	(447,029)	(380,632)	(312,131)
Dividends paid on preferred stock	(4,141)	(5,207)	(9,619)
Contributions from and sales of noncontrolling interests	1,022,712	28,275	44,931
Distributions to and purchases of noncontrolling interests	(48,225)	(32,253)	(22,361)
Net cash provided by financing activities	2,927,482	1,588,433	1,420,341
Effect of foreign exchange rate changes on cash and cash equivalents	540	(2,068)	1,723
Net increase (decrease) in cash, cash equivalents, and restricted cash	(29,441)	(5,056)	135,820
Cash, cash equivalents, and restricted cash as of the beginning of period	272,130	277,186	141,366
Cash, cash equivalents, and restricted cash as of the end of period	242,689	272,130	277,186
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	146,165	127,093	112,113
Supplemental Disclosure and Non-Cash Investing and Financing Activities:
Change in accrued construction	(24)	81,177	(11,034)
Accrued construction for current-period additions to real estate	220,773	244,147	179,154
Assumption of secured notes payable in connection with purchase of properties	(28,200)	0	0
Right-of-use asset	269,189	0	0
Lease liability	(275,175)	0	0
Contribution of real estate from noncontrolling interests	115,167	0	8,597
Issuance of common stock for conversion of 7.00% Series D preferred stock	57,461	0	0
Payable for purchase of real estate	0	(65,000)	0
Contribution of real estate to an unconsolidated real estate joint venture	0	0	6,998
Eliminations
Operating Activities
Net income (loss)	(1,158,401)	(1,056,573)	(672,537)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	0	0	0
Loss on early extinguishment of debt	0	0	0
Impairment of real estate	0	0	0
Gain on sales of real estate – rental properties	0	0	0
Gain on sales of real estate - land parcels			0
Equity in earnings of unconsolidated real estate joint ventures	0	0	0
Distributions of earnings from unconsolidated real estate joint ventures	0	0	0
Amortization of loan fees	0	0	0
Amortization of debt discount (premiums)	0	0	0
Amortization of acquired below-market leases	0	0	0
Deferred rent	0	0	0
Stock compensation expense	0	0	0
Equity in earnings of affiliates	1,158,401	1,056,573	672,537
Investment income	0	0	0
Changes in operating assets and liabilities:
Tenant receivables	0	0	0
Deferred leasing costs	0	0	0
Other assets	0	0	0
Accounts payable, accrued expenses, and tenant security deposits	0	0	0
Net cash provided by operating activities	0	0	0
Investing Activities
Proceeds from sales of real estate	0	0	0
Additions to real estate	0	0	0
Purchase of real estate	0	0	0
Deposits for investing activities	0	0	0
Investments in subsidiaries	5,166,822	3,186,913	2,742,690
Acquisition of interest in unconsolidated real estate joint venture		0	0
Investments in unconsolidated real estate joint venture	0	0	0
Return of capital from unconsolidated real estate joint ventures	0	0	0
Additions to investments	0	0	0
Sales of investments	0	0	0
Net cash used in investing activities	5,166,822	3,186,913	2,742,690
Financing Activities
Borrowings from secured notes payable		0	0
Repayments of borrowings from secured notes payable	0	0	0
Proceeds from issuance of unsecured senior notes payable	0	0	0
Repayments of unsecured senior notes payable	0
Borrowings from unsecured senior line of credit	0	0	0
Repayments of borrowings from unsecured senior line of credit	0	0	0
Proceeds from issuance of commercial paper program	0
Repayments of borrowings from commercial paper program	0
Repayment of unsecured senior bank term loan	0	0	0
Premium paid for early extinguishment of debt	0
Transfers to/from parent company	(5,166,822)	(3,186,913)	(2,742,690)
Payment of loan fees	0	0	0
Taxes paid related to net settlement of equity awards	0
Repurchase of 7.00% Series D convertible preferred stock	0	0	0
Redemption of 6.45% Series E redeemable preferred stock			0
Proceeds from the issuance of common stock	0	0	0
Dividends paid on common stock	0	0	0
Dividends paid on preferred stock	0	0	0
Contributions from and sales of noncontrolling interests	0	0	0
Distributions to and purchases of noncontrolling interests	0	0	0
Net cash provided by financing activities	(5,166,822)	(3,186,913)	(2,742,690)
Effect of foreign exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash, cash equivalents, and restricted cash	0	0	0
Cash, cash equivalents, and restricted cash as of the beginning of period	0	0	0
Cash, cash equivalents, and restricted cash as of the end of period	0	0	0
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	0	0	0
Supplemental Disclosure and Non-Cash Investing and Financing Activities:
Change in accrued construction	0	0	0
Accrued construction for current-period additions to real estate	0	0	0
Assumption of secured notes payable in connection with purchase of properties	0
Right-of-use asset	0
Lease liability	0
Contribution of real estate from noncontrolling interests	0		0
Issuance of common stock for conversion of 7.00% Series D preferred stock	0
Payable for purchase of real estate		0
Contribution of real estate to an unconsolidated real estate joint venture			0
Alexandria Real Estate Equities, Inc. (Issuer)
Operating Activities
Net income (loss)	363,165	379,312	169,093
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,949	6,339	7,625
Loss on early extinguishment of debt	40,209	823	670
Impairment of real estate	0	0	0
Gain on sales of real estate – rental properties	0	0	0
Gain on sales of real estate - land parcels			0
Equity in earnings of unconsolidated real estate joint ventures	0	0	0
Distributions of earnings from unconsolidated real estate joint ventures	0	0	0
Amortization of loan fees	8,780	8,777	7,627
Amortization of debt discount (premiums)	(573)	797	608
Amortization of acquired below-market leases	0	0	0
Deferred rent	0	0	0
Stock compensation expense	43,640	35,019	25,610
Equity in earnings of affiliates	(658,364)	(591,942)	(337,923)
Investment income	0	0	0
Changes in operating assets and liabilities:
Tenant receivables	0	0	0
Deferred leasing costs	0	0	0
Other assets	(7,171)	(14,701)	(9,343)
Accounts payable, accrued expenses, and tenant security deposits	22,076	20,663	(10,524)
Net cash provided by operating activities	(181,289)	(154,913)	(146,557)
Investing Activities
Proceeds from sales of real estate	0	0	0
Additions to real estate	0	0	0
Purchase of real estate	0	0	0
Deposits for investing activities	0	0	0
Investments in subsidiaries	(2,604,416)	(1,693,774)	(1,458,973)
Acquisition of interest in unconsolidated real estate joint venture		0	0
Investments in unconsolidated real estate joint venture	0	0	0
Return of capital from unconsolidated real estate joint ventures	0	0	0
Additions to investments	0	0	0
Sales of investments	0	0	0
Net cash used in investing activities	(2,604,416)	(1,693,774)	(1,458,973)
Financing Activities
Borrowings from secured notes payable		0	0
Repayments of borrowings from secured notes payable	0	0	0
Proceeds from issuance of unsecured senior notes payable	2,721,169	899,321	1,023,262
Repayments of unsecured senior notes payable	(950,000)
Borrowings from unsecured senior line of credit	5,056,000	4,741,000	3,858,000
Repayments of borrowings from unsecured senior line of credit	(4,880,000)	(4,583,000)	(3,836,000)
Proceeds from issuance of commercial paper program	2,233,000
Repayments of borrowings from commercial paper program	(2,233,000)
Repayment of unsecured senior bank term loan	(350,000)	(200,000)	(200,000)
Premium paid for early extinguishment of debt	(34,677)
Transfers to/from parent company	404,556	105,961	64,156
Payment of loan fees	(26,774)	(19,292)	(9,440)
Taxes paid related to net settlement of equity awards	(25,477)
Repurchase of 7.00% Series D convertible preferred stock	(9,240)	(13,976)	(17,934)
Redemption of 6.45% Series E redeemable preferred stock			(130,350)
Proceeds from the issuance of common stock	1,216,445	1,293,301	1,275,397
Dividends paid on common stock	(447,029)	(380,632)	(312,131)
Dividends paid on preferred stock	(4,141)	(5,207)	(9,619)
Contributions from and sales of noncontrolling interests	0	0	0
Distributions to and purchases of noncontrolling interests	0	0	0
Net cash provided by financing activities	2,670,832	1,837,476	1,705,341
Effect of foreign exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash, cash equivalents, and restricted cash	(114,873)	(11,211)	99,811
Cash, cash equivalents, and restricted cash as of the beginning of period	119,305	130,516	30,705
Cash, cash equivalents, and restricted cash as of the end of period	4,432	119,305	130,516
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	133,033	104,935	85,705
Supplemental Disclosure and Non-Cash Investing and Financing Activities:
Change in accrued construction	0	0	0
Accrued construction for current-period additions to real estate	0	0	0
Assumption of secured notes payable in connection with purchase of properties	0
Right-of-use asset	0
Lease liability	0
Contribution of real estate from noncontrolling interests	0		0
Issuance of common stock for conversion of 7.00% Series D preferred stock	57,461
Payable for purchase of real estate		0
Contribution of real estate to an unconsolidated real estate joint venture			0
Alexandria Real Estate Equities, L.P. (Guarantor Subsidiary)
Operating Activities
Net income (loss)	490,427	456,102	325,655
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	0	0	0
Loss on early extinguishment of debt	0	0	0
Impairment of real estate	0	0	0
Gain on sales of real estate – rental properties	0	0	0
Gain on sales of real estate - land parcels			0
Equity in earnings of unconsolidated real estate joint ventures	0	0	0
Distributions of earnings from unconsolidated real estate joint ventures	0	0	0
Amortization of loan fees	0	0	0
Amortization of debt discount (premiums)	0	0	0
Amortization of acquired below-market leases	0	0	0
Deferred rent	0	0	0
Stock compensation expense	0	0	0
Equity in earnings of affiliates	(490,393)	(455,574)	(328,230)
Investment income	(34)	(528)	2,575
Changes in operating assets and liabilities:
Tenant receivables	0	0	0
Deferred leasing costs	0	0	0
Other assets	0	0	0
Accounts payable, accrued expenses, and tenant security deposits	0	0	0
Net cash provided by operating activities	0	0	0
Investing Activities
Proceeds from sales of real estate	0	0	0
Additions to real estate	0	0	0
Purchase of real estate	0	0	0
Deposits for investing activities	0	0	0
Investments in subsidiaries	(2,510,826)	(1,463,063)	(1,257,845)
Acquisition of interest in unconsolidated real estate joint venture		0	0
Investments in unconsolidated real estate joint venture	0	0	0
Return of capital from unconsolidated real estate joint ventures	0	0	0
Additions to investments	0	0	0
Sales of investments	282	956	208
Net cash used in investing activities	(2,510,544)	(1,462,107)	(1,257,637)
Financing Activities
Borrowings from secured notes payable		0	0
Repayments of borrowings from secured notes payable	0	0	0
Proceeds from issuance of unsecured senior notes payable	0	0	0
Repayments of unsecured senior notes payable	0
Borrowings from unsecured senior line of credit	0	0	0
Repayments of borrowings from unsecured senior line of credit	0	0	0
Proceeds from issuance of commercial paper program	0
Repayments of borrowings from commercial paper program	0
Repayment of unsecured senior bank term loan	0	0	0
Premium paid for early extinguishment of debt	0
Transfers to/from parent company	2,510,544	1,462,098	1,257,646
Payment of loan fees	0	0	0
Taxes paid related to net settlement of equity awards	0
Repurchase of 7.00% Series D convertible preferred stock	0	0	0
Redemption of 6.45% Series E redeemable preferred stock			0
Proceeds from the issuance of common stock	0	0	0
Dividends paid on common stock	0	0	0
Dividends paid on preferred stock	0	0	0
Contributions from and sales of noncontrolling interests	0	0	0
Distributions to and purchases of noncontrolling interests	0	0	0
Net cash provided by financing activities	2,510,544	1,462,098	1,257,646
Effect of foreign exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash, cash equivalents, and restricted cash	0	(9)	9
Cash, cash equivalents, and restricted cash as of the beginning of period	0	9	0
Cash, cash equivalents, and restricted cash as of the end of period	0	0	9
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	0	0	0
Supplemental Disclosure and Non-Cash Investing and Financing Activities:
Change in accrued construction	0	0	0
Accrued construction for current-period additions to real estate	0	0	0
Assumption of secured notes payable in connection with purchase of properties	0
Right-of-use asset	0
Lease liability	0
Contribution of real estate from noncontrolling interests	0		0
Issuance of common stock for conversion of 7.00% Series D preferred stock	0
Payable for purchase of real estate		0
Contribution of real estate to an unconsolidated real estate joint venture			0
Combined Non- Guarantor Subsidiaries
Operating Activities
Net income (loss)	708,856	623,952	371,993
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	537,663	471,322	409,158
Loss on early extinguishment of debt	7,361	299	2,781
Impairment of real estate	12,334	6,311	203
Gain on sales of real estate – rental properties	(474)	(8,704)	(270)
Gain on sales of real estate - land parcels			(111)
Equity in earnings of unconsolidated real estate joint ventures	(10,136)	(43,981)	(15,426)
Distributions of earnings from unconsolidated real estate joint ventures	2,796	430	1,618
Amortization of loan fees	325	1,494	3,522
Amortization of debt discount (premiums)	(3,204)	(3,203)	(3,120)
Amortization of acquired below-market leases	(29,813)	(21,938)	(19,055)
Deferred rent	(104,235)	(93,883)	(107,643)
Stock compensation expense	0	0	0
Equity in earnings of affiliates	(9,644)	(9,057)	(6,384)
Investment income	(194,613)	(136,235)	(3,904)
Changes in operating assets and liabilities:
Tenant receivables	(897)	435	(502)
Deferred leasing costs	(54,455)	(57,088)	(62,639)
Other assets	(13,654)	(6,148)	(8,879)
Accounts payable, accrued expenses, and tenant security deposits	16,936	1,246	36,097
Net cash provided by operating activities	865,146	725,252	597,439
Investing Activities
Proceeds from sales of real estate	6,619	20,190	15,432
Additions to real estate	(1,224,541)	(927,168)	(893,685)
Purchase of real estate	(2,259,778)	(1,037,180)	(675,584)
Deposits for investing activities	(18,107)	(2,000)	(2,300)
Investments in subsidiaries	(51,580)	(30,076)	(25,872)
Acquisition of interest in unconsolidated real estate joint venture		(35,922)	(60,291)
Investments in unconsolidated real estate joint venture	(102,081)	(116,008)	(17,876)
Return of capital from unconsolidated real estate joint ventures	14	68,592	38,576
Additions to investments	(190,778)	(235,943)	(171,881)
Sales of investments	147,050	102,723	30,275
Net cash used in investing activities	(3,693,182)	(2,192,792)	(1,763,206)
Financing Activities
Borrowings from secured notes payable		17,784	153,405
Repayments of borrowings from secured notes payable	(306,199)	(156,888)	(396,240)
Proceeds from issuance of unsecured senior notes payable	0	0	0
Repayments of unsecured senior notes payable	0
Borrowings from unsecured senior line of credit	0	0	0
Repayments of borrowings from unsecured senior line of credit	0	0	0
Proceeds from issuance of commercial paper program	0
Repayments of borrowings from commercial paper program	0
Repayment of unsecured senior bank term loan	0	0	0
Premium paid for early extinguishment of debt	(6,674)
Transfers to/from parent company	2,251,722	1,618,854	1,420,888
Payment of loan fees	(408)	0	(579)
Taxes paid related to net settlement of equity awards	0
Repurchase of 7.00% Series D convertible preferred stock	0	0	0
Redemption of 6.45% Series E redeemable preferred stock			0
Proceeds from the issuance of common stock	0	0	0
Dividends paid on common stock	0	0	0
Dividends paid on preferred stock	0	0	0
Contributions from and sales of noncontrolling interests	1,022,712	28,275	44,931
Distributions to and purchases of noncontrolling interests	(48,225)	(32,253)	(22,361)
Net cash provided by financing activities	2,912,928	1,475,772	1,200,044
Effect of foreign exchange rate changes on cash and cash equivalents	540	(2,068)	1,723
Net increase (decrease) in cash, cash equivalents, and restricted cash	85,432	6,164	36,000
Cash, cash equivalents, and restricted cash as of the beginning of period	152,825	146,661	110,661
Cash, cash equivalents, and restricted cash as of the end of period	238,257	152,825	146,661
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	13,132	22,158	26,408
Supplemental Disclosure and Non-Cash Investing and Financing Activities:
Change in accrued construction	(24)	81,177	(11,034)
Accrued construction for current-period additions to real estate	220,773	244,147	179,154
Assumption of secured notes payable in connection with purchase of properties	(28,200)
Right-of-use asset	269,189
Lease liability	(275,175)
Contribution of real estate from noncontrolling interests	115,167		8,597
Issuance of common stock for conversion of 7.00% Series D preferred stock	$ 0
Payable for purchase of real estate		$ (65,000)
Contribution of real estate to an unconsolidated real estate joint venture			$ 6,998