Area of a real estate property.

No definition available.

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482130/360-10-45-5

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3

+ Details

Name:	us-gaap_GainLossOnSaleOfProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from the sale of formerly productive land held for sale, anything permanently fixed to it, including buildings, structures on it, and so forth.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-12

+ Details

Name:	us-gaap_ProceedsFromSaleOfPropertyHeldForSale
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

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Balance Type:	na
Period Type:	duration

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=are_A550ArsenalStreetMember
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- Details

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- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=are_A601KeystoneParkDriveMember
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- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=are_A2285RutherfordRoadAnd7TriangleDriveMember
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- Details

Name:	are_PropertyTypeAxis=are_OperatingPropertiesMember
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- Details

Name:	are_PropertyTypeAxis=are_FutureDevelopmentProjectsMember
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Subsequent events (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
Subsequent events (Details) $ in Thousands	Oct. 31, 2025 USD ($)	Sep. 30, 2025 USD ($) ft²	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) ft²	Sep. 30, 2024 USD ($)
Subsequent Event [Line Items]
Gain on sales of real estate		$ 9,366	$ 27,114	$ 22,531	$ 27,506
Proceeds from sales of real estate				$ 227,105	$ 229,790
550 Arsenal Street \| Subsequent Event
Subsequent Event [Line Items]
Gain on sales of real estate	$ 0
Proceeds from sales of real estate	99,300
601 Keystone Park Drive \| Subsequent Event
Subsequent Event [Line Items]
Gain on sales of real estate	4,400
2285 Rutherford Road and 7 Triangle Drive \| Subsequent Event
Subsequent Event [Line Items]
Proceeds from sales of real estate	$ 68,100
Operating Properties \| 550 Arsenal Street
Subsequent Event [Line Items]
Area of real estate property \| ft²		249,275		249,275
Operating Properties \| 2285 Rutherford Road and 7 Triangle Drive
Subsequent Event [Line Items]
Area of real estate property \| ft²		206,340		206,340
Future Development Projects \| 550 Arsenal Street
Subsequent Event [Line Items]
Area of real estate property \| ft²		281,592		281,592