Earnings Per Share (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Earnings Per Share [Abstract]
Repurchases of common stock (in shares)			0	175,735
Weighted Average Number of Shares, Treasury Stock		83,000		27,000
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	149,000	124,000	144,000	118,000
Net (loss) income for basic calculation	$ (14,355,000)	$ 4,960,000	$ (10,440,000)	$ 17,770,000
Numerator for diluted calculation	$ (14,355,000)	$ 4,960,000	$ (10,440,000)	$ 17,770,000
Denominator for basic calculation (in shares)	16,195,000	16,202,000	16,184,000	16,220,000
Dilutive effect on shares of stock-based awards (in shares)	0	180,000	0	248,000
Denominator for diluted calculation (in shares)	16,195,000	16,382,000	16,184,000	16,468,000
Stock options and RSUs [Member]
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)	2,362,000	685,000	2,365,000	477,000