Returns all Sales Invoices - Not getting all details of invoices in list as given in response sample

[Team Paul]

I am using  'https://api.accounting.sage.com/v3.1/sales_invoices' this endpoint to get all sales invoices list, But API is not getting all details. It is only returning 

collection in this format  {"id": "XXXXXXXX", displayed_as": "SI-",$path": "/sales_invoices/586117de375711e8b45c025132dab352"}.

How can we get all data as suggested in the API guideline.