Equity - Restricted net assets (Details) - USD ($)	Jun. 30, 2020	Jun. 30, 2019
Equity
Statutory reserves	$ 1,670,367	$ 1,496,642
Restricted net assets	$ 17,978,793	$ 18,571,570

A segregation of retained earnings which is unavailable for dividend distribution. Includes also retained earnings appropriated for loss contingencies.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant