Investments in real estate - Real estate asset sales (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2025 USD ($) ft²	Jun. 30, 2025 USD ($) ft² property	Dec. 31, 2025 USD ($) ft² property	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2020 USD ($)
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 2,320,875	$ 1,220,206	$ 1,195,743
Gain on sales of real estate			642,445	129,312	277,037
Impairment of real estate			2,202,818	223,068	461,114
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			1,118,854	272,233	243,268
Notes Receivable
Real Estate Properties [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent			$ 18,089
601, 611, 651, 681, 685, 701, and 751 Gateway Boulevard
Real Estate Properties [Line Items]
Building occupancy			62.00%
Noncontrolling Interests
Real Estate Properties [Line Items]
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			$ 1,045,489	264,149	$ 243,268
Additional Paid-In Capital
Real Estate Properties [Line Items]
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			$ 73,365	8,084
550 Arsenal Street
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 99,250
Gain on sales of real estate			0
Impairment of real estate			$ 43,400
550 Arsenal Street | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			249,275
550 Arsenal Street | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²	281,592		281,592
285, 299, 307, and 345 Dorchester Avenue
Real Estate Properties [Line Items]
Gain on sales of real estate			$ 0
Impairment of real estate			$ 236,000
285, 299, 307, and 345 Dorchester Avenue | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
285, 299, 307, and 345 Dorchester Avenue | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			1,040,000
409 and 499 Illinois Street
Real Estate Properties [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries			$ 721,100
Gross sales price of real estate			767,100
Gain on sales of real estate			$ 416,749
Building occupancy			40.00%
Weighted average remaining lease term			8 years 3 months 18 days
409 and 499 Illinois Street | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			466,297
409 and 499 Illinois Street | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
601, 611, 651, 681, 685, 701, and 751 Gateway Boulevard
Real Estate Properties [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries			$ 560,400
Gross sales price of real estate			600,000
Gain on sales of real estate			0
Impairment of real estate			$ 385,000
Weighted average remaining lease term			5 years 1 month 6 days
601, 611, 651, 681, 685, 701, and 751 Gateway Boulevard | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			1,104,826
601, 611, 651, 681, 685, 701, and 751 Gateway Boulevard | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			528,684
601, 611, 651, 681, 685, 701, and 751 Gateway Boulevard | Operating with future development and redevelopment
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			1,600,000
2425 Garcia Avenue and 2400/2450 Bayshore Parkway
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 11,000
Gain on sales of real estate			$ 0
2425 Garcia Avenue and 2400/2450 Bayshore Parkway | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			95,901
2425 Garcia Avenue and 2400/2450 Bayshore Parkway | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
ARE Nautilus
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 192,000
Gain on sales of real estate			$ 86,260
ARE Nautilus | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			218,640
ARE Nautilus | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
Costa Verde By Alexandria
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 124,000
Gain on sales of real estate			0
Costa Verde By Alexandria | Notes Receivable
Real Estate Properties [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent			$ 91,000
Costa Verde By Alexandria | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			8,730
Costa Verde By Alexandria | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			537,000
4767 Nexus Center Drive
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 50,000
Gain on sales of real estate			15,330
4767 Nexus Center Drive | Notes Receivable
Real Estate Properties [Line Items]
Financing Receivable, before Allowance for Credit Loss, Noncurrent			$ 33,000
4767 Nexus Center Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			65,280
4767 Nexus Center Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
9363, 9373, and 9393 Towne Centre Drive
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 40,000
Gain on sales of real estate			$ 17,978
9363, 9373, and 9393 Towne Centre Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
9363, 9373, and 9393 Towne Centre Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			230,000
Pacific Technology Park
Real Estate Properties [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries	$ 96,000
Gain on sales of real estate	9,300		$ 9,290
Number of real estate properties | property		5
Pacific Technology Park | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²		544,352
Pacific Technology Park | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
6260 Sequence Drive
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 70,000
Gain on sales of real estate			$ 0
6260 Sequence Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			130,536
6260 Sequence Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
5505 Morehouse Drive
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 45,000
Gain on sales of real estate			$ 0
5505 Morehouse Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			79,945
5505 Morehouse Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
5600 Avenida Encinas
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 64,100
Gain on sales of real estate			0
Impairment of real estate	$ 7,000	$ 35,400	$ 42,400
5600 Avenida Encinas | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			182,276
5600 Avenida Encinas | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
21540 30th Drive Southeast
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 43,829
Gain on sales of real estate			$ 0
21540 30th Drive Southeast | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			144,738
21540 30th Drive Southeast | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
14 TW Alexander Drive
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 155,000
Gain on sales of real estate			$ 78,489
14 TW Alexander Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			173,820
14 TW Alexander Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
3029 East Cornwallis Road
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 29,500
Gain on sales of real estate			0
Impairment of real estate			$ 82,500
3029 East Cornwallis Road | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
3029 East Cornwallis Road | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			600,000
601 Keystone Park Drive
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 24,879
Gain on sales of real estate			$ 4,362
601 Keystone Park Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			77,595
601 Keystone Park Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
Alexandria Center for Life Science - Long Island City
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 34,500
Gain on sales of real estate			$ 0
Alexandria Center for Life Science - Long Island City | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			179,100
Alexandria Center for Life Science - Long Island City | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
Other - Texas
Real Estate Properties [Line Items]
Real Estate Property, Ownership Interest Sold			100.00%
Proceeds from sales of real estate			$ 73,287
Gain on sales of real estate			$ 0
Other - Texas | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			0
Other - Texas | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			1,350,000
Other Dispositions
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 258,917
Gain on sales of real estate			13,987
Gateway and Illinois Properties | Noncontrolling Interests
Real Estate Properties [Line Items]
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			685,400
One Hampshire Street and 100 Edwin H. Land Boulevard
Real Estate Properties [Line Items]
Impairment of real estate			262,100
Potential Asset Disposition, Consideration			$ 116,400
One Hampshire Street and 100 Edwin H. Land Boulevard | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			279,456
10256 and 10260 Meanley Drive
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 14,600
Gain on sales of real estate			0
Impairment of real estate			$ 27,800
10256 and 10260 Meanley Drive | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²	154,308
6260 Sequence Drive and 5505 Morehouse Drive
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			210,481
Proceeds from sales of real estate			$ 115,000
Gain on sales of real estate			0
Impairment of real estate			$ 17,300
Number of real estate properties | property			2
Sorrento Mesa and University Town Center properties
Real Estate Properties [Line Items]
Impairment of real estate			$ 31,700
Number of real estate properties | property			7
Potential Asset Disposition, Consideration			$ 117,800
Sorrento Mesa and University Town Center properties | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			330,192
SoMa and Greater Stanford properties
Real Estate Properties [Line Items]
Impairment of real estate			$ 478,100
Potential Asset Disposition, Consideration			$ 205,800
Gain (Loss) on Termination of Lease						$ 89,500
SoMa and Greater Stanford properties | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			228,000
SoMa and Greater Stanford properties | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			1,300,000
7 Triangle Drive
Real Estate Properties [Line Items]
Impairment of real estate			$ 31,800
Number of real estate properties | property			1
Potential Asset Disposition, Consideration			$ 1,200
7 Triangle Drive | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²	104,531
30-02 48th Avenue
Real Estate Properties [Line Items]
Impairment of real estate			$ 206,200
Building occupancy	52.00%
30-02 48th Avenue | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			179,100
Bothell properties
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 60,100
Gain on sales of real estate			0
Impairment of real estate			$ 28,200
Number of real estate properties | property			3
Bothell properties | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			250,132
Montreal properties
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			787,698
Impairment of real estate			$ 107,100
Number of real estate properties | property			10
Potential Asset Disposition, Consideration			$ 140,500
Non-cluster - Los Angeles properties
Real Estate Properties [Line Items]
Proceeds from sales of real estate			37,500
Gain on sales of real estate			0
Impairment of real estate			$ 71,900
Number of real estate properties | property			4
Non-cluster - Los Angeles properties | Operating property
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			182,626
Non-cluster - Miami properties
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 30,300
Gain on sales of real estate			0
Impairment of real estate			47,300
Non-cluster - Miami properties | Future development
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²	374,349
Other - ROUA properties
Real Estate Properties [Line Items]
Impairment of real estate			45,100
Other - Various markets
Real Estate Properties [Line Items]
Proceeds from sales of real estate			170,400
Gain on sales of real estate			30,600
Impairment of real estate			59,000
Potential Asset Disposition, Consideration			129,400
Alexandria Center for Life Science - New York City
Real Estate Properties [Line Items]
Gross investments in real estate			178,100
Alexandria | 285, 299, 307, and 345 Dorchester Avenue
Real Estate Properties [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries			33,500
Impairment of real estate			$ 149,700
Noncontrolling interest, ownership percentage by parent			60.00%
Alexandria | 409 and 499 Illinois Street
Real Estate Properties [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries			$ 180,273
Gain on sales of real estate			$ 103,900
Noncontrolling interest, ownership percentage by parent			25.00%
Alexandria | 601, 611, 651, 681, 685, 701, and 751 Gateway Boulevard
Real Estate Properties [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries			$ 283,173
Impairment of real estate			$ 206,000
Alexandria | Pacific Technology Park
Real Estate Properties [Line Items]
Noncontrolling interest, ownership percentage by parent	50.00%	50.00%
Alexandria | 751 Gateway Boulevard
Real Estate Properties [Line Items]
Noncontrolling interest, ownership percentage by parent			51.00%
Alexandria | 601, 611, 651, 681, 685, and 701 Gateway Boulevard
Real Estate Properties [Line Items]
Noncontrolling interest, ownership percentage by parent			50.00%
North America
Real Estate Properties [Line Items]
Area of Real Estate Property | ft²			35,900,000
Proceeds from sales of real estate			$ 1,813,778
Gain on sales of real estate			$ 642,445
Number of real estate properties | property			340
Gross investments in real estate			$ 34,103,488	$ 37,214,474