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.

No definition available.

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

Earnings (Loss) Per Share (Details 1) - shares	3 Months Ended		6 Months Ended
Earnings (Loss) Per Share (Details 1) - shares	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016
Class B Common Stock [Member] \| Stock options [Member]
Class of Stock [Line Items]
Stock options	88		88