Members' capital (Distributions to Other Members) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Distributions	$ 96	$ 513
Weighted average number of Units outstanding	2,554,249	2,565,749
Other Members [Member]
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Distributions	$ 96	$ 513
Weighted average number of Units outstanding	2,554,249	2,565,749
Weighted average distributions per Unit	$ 0.04	$ 0.2

Weighted average number of limited liability company units outstanding determined by relating the portion of time within a reporting period that limited liability company units have been outstanding to the total time in that period.

No definition available.

+ Details

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Namespace Prefix:	atel_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of equity impact of cash distributions declared to unit-holder of limited liability company (LLC).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 272
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483014/272-10-45-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

+ Details

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

- Definition

Per unit of ownership amount of cash distributions paid to unit-holder of a limited liability company (LLC).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: