Loss Per Share (Details) - shares	3 Months Ended
Oct. 31, 2019	Oct. 31, 2018
Shares were excluded from the diluted earnings per share computations
Shares excluded from the calculation of diluted earnings per share	1,806	1,292
Stock options [Member]
Shares were excluded from the diluted earnings per share computations
Shares excluded from the calculation of diluted earnings per share	1,190	1,243
Non-vested restricted Class B common stock [Member]
Shares were excluded from the diluted earnings per share computations
Shares excluded from the calculation of diluted earnings per share	616	49

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration