Earnings Per Share (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average performance shares outstanding during the period that are excluded from EPS Calculation (in shares)	227,000	149,000	233,000	144,000
Net income (loss) for basic calculation	$ 4,417,000	$ (14,355,000)	$ 8,513,000	$ (10,440,000)
Numerator for diluted calculation	$ 4,417,000	$ (14,355,000)	$ 8,513,000	$ (10,440,000)
Denominator for basic calculation (in shares)	23,449,000	16,195,000	23,420,000	16,184,000
Dilutive effect on shares of stock-based awards (in shares)	54,000	0	29,000	0
Denominator for diluted calculation (in shares)	23,503,000	16,195,000	23,449,000	16,184,000
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)	1,912,000	2,362,000	2,227,000	2,365,000