Summary of Significant Accounting and Reporting Policies (Earnings Per Share) (Details) - USD ($)	3 Months Ended												12 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Accounting Policies [Abstract]
Reduction in weighted average shares as a result of the repurchase of common shares (in shares)													0	0	0
Weighted average performance shares outstanding during the period that are excluded from EPS calculation													201,000	243,000	258,000
Numerator:
Net income for basic calculation	$ 1,126,000	$ (3,989,000)	$ 3,495,000	$ 6,388,000	$ 6,135,000	$ 7,612,000	$ 7,826,000	$ 3,468,000	$ 7,458,000	$ 8,210,000	$ 15,761,000	$ (1,660,000)	$ 7,020,000	$ 25,041,000	$ 29,769,000
Numerator for diluted calculation													$ 7,020,000	$ 25,041,000	$ 29,769,000
Denominator:
Denominator for basic calculation (in shares)													24,798,000	24,124,000	23,825,000
Effect of dilutive securities:
Stock-based awards (in shares)													101,000	178,000	215,000
Denominator for diluted calculation (in shares)													24,899,000	24,302,000	24,040,000
Stock-based Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive equity-classified stock-based awards not included in calculation of diluted earnings per share (in shares)													1,348,000	1,347,000	1,739,000