Summary of Significant Accounting Policies - Other (Details) - USD ($)	12 Months Ended
Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Stock-Based Compensation
Dividend yield (as a percent)	0.20%
Advertising Costs
Advertising costs charged to expense	$ 3,349,000	$ 3,333,000	$ 2,656,000

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration