Earnings Per Share (Details) - USD ($)	3 Months Ended	6 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchased during period (in shares)	0	0	0	0
Weighted average performance shares outstanding during the period that are excluded from EPS Calculation (in shares)	203,000	245,000	196,000	240,000
Numerator:
Net income for basic calculation	$ 3,495,000	$ 7,826,000	$ 9,883,000	$ 11,294,000
Numerator for diluted calculation	$ 3,495,000	$ 7,826,000	$ 9,883,000	$ 11,294,000
Denominator:
Denominator for basic calculation (in shares)	24,659,000	24,034,000	24,607,000	24,017,000
Effect of dilutive securities: Stock-based awards (in shares)	399,000	134,000	297,000	228,000
Denominator for diluted calculation (in shares)	25,058,000	24,168,000	24,904,000	24,245,000
Stock options, performance shares (with the performance conditions satisfied), RSUs and restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive equity-classified stock-based awards not included in calculation of diluted earnings per share (in shares)		1,678,000	178,000	609,000

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Weighted average number of RSUs with performance measures (which we refer to as performance shares) outstanding during the period, which are excluded from calculation of basic and diluted earnings per share as the respective performance conditions have not yet been satisfied.

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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.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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