Operations and summary of significant accounting policies (Details 2- Basis of presentation)	Dec. 31, 2021
Equity investment method and Variable Interest Entity
Ownership percentage of investments in companies below which the entity must exercise significant influence in order to be accounted for under the equity method	20.00%
Minimum
Equity investment method and Variable Interest Entity
Equity Method Investment, Ownership Percentage	20.00%

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant