Condensed Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]
Beginning balance at Jul. 31, 2014	$ 396,925,000	$ 3,102,000	$ 421,240,000	$ 409,443,000	$ (436,860,000)
Common stock, beginning balance (in shares) at Jul. 31, 2014		31,016,469
Treasury stock, beginning balance (in shares) at Jul. 31, 2014					14,857,582
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-classified stock award compensation	3,642,000		3,642,000
Proceeds from exercise of options	1,417,000	$ 5,000	1,412,000
Proceeds from exercise of options (in shares)		49,200
Proceeds from issuance of employee stock purchase plan shares	707,000	$ 2,000	705,000
Proceeds from issuance of employee stock purchase plan shares (in shares)		25,768
Common stock issued for net settlement of stock-based awards	(420,000)	$ 6,000	(426,000)
Common stock issued for net settlement of stock-based awards (in shares)		60,120
Cash dividends declared	(14,567,000)			(14,567,000)
Accrual of dividend equivalents, net of reversal	(169,000)			(169,000)
Net income tax shortfall from settlement of stock-based awards	(248,000)		(248,000)
Reversal of deferred tax asset associated with debt converted to shares of common stock	(58,000)		(58,000)
Reversal of deferred tax assets associated with expired and unexercised stock-based awards	(12,000)		(12,000)
Repurchases of common stock	$ (4,989,000)				$ (4,989,000)
Repurchases of common stock (in shares)	175,735				175,735
Net (loss) income	$ 17,770,000			17,770,000
Ending balance at Apr. 30, 2015	399,998,000	$ 3,115,000	426,255,000	412,477,000	$ (441,849,000)
Common stock, ending balance (in shares) at Apr. 30, 2015		31,151,557
Treasury stock, ending balance (in shares) at Apr. 30, 2015					15,033,317
Beginning balance at Jul. 31, 2015	$ 401,409,000	$ 3,117,000	427,083,000	413,058,000	$ (441,849,000)
Common stock, beginning balance (in shares) at Jul. 31, 2015	31,165,401	31,165,401
Treasury stock, beginning balance (in shares) at Jul. 31, 2015	15,033,317				15,033,317
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity-classified stock award compensation	$ 3,125,000		3,125,000
Proceeds from issuance of employee stock purchase plan shares	499,000	$ 3,000	496,000
Proceeds from issuance of employee stock purchase plan shares (in shares)		29,070
Common stock issued for net settlement of stock-based awards	(74,000)	$ 1,000	(75,000)
Common stock issued for net settlement of stock-based awards (in shares)		9,925
Cash dividends declared	(14,544,000)			(14,544,000)
Accrual of dividend equivalents, net of reversal	(97,000)			(97,000)
Net income tax shortfall from settlement of stock-based awards	(25,000)		(25,000)
Reversal of deferred tax assets associated with expired and unexercised stock-based awards	$ (55,000)		(55,000)
Repurchases of common stock (in shares)	0
Net (loss) income	$ (10,440,000)			(10,440,000)
Ending balance at Apr. 30, 2016	$ 379,798,000	$ 3,121,000	$ 430,549,000	$ 387,977,000	$ (441,849,000)
Common stock, ending balance (in shares) at Apr. 30, 2016	31,204,396	31,204,396
Treasury stock, ending balance (in shares) at Apr. 30, 2016	15,033,317				15,033,317