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	2,398,000		2,398,000
Proceeds from exercise of options	119,000	$ 0	119,000
Proceeds from exercise of options (in shares)		4,200
Proceeds from issuance of employee stock purchase plan shares	479,000	$ 2,000	477,000
Proceeds from issuance of employee stock purchase plan shares (in shares)		16,491
Common stock issued for net settlement of stock-based awards	(389,000)	$ 6,000	(395,000)
Common stock issued for net settlement of stock-based awards (in shares)		58,577
Cash dividends declared	(9,732,000)			(9,732,000)
Accrual of dividend equivalents, net of reversal	(113,000)			(113,000)
Net income tax shortfall from settlement of stock-based awards	(149,000)		(149,000)
Reversal of deferred tax assets associated with expired and unexercised stock-based awards	(12,000)		(12,000)
Net income	12,810,000			12,810,000
Ending balance at Jan. 31, 2015	402,336,000	$ 3,110,000	423,678,000	412,408,000	$ (436,860,000)
Common stock, ending balance (in shares) at Jan. 31, 2015		31,095,737
Treasury stock, ending balance (in shares) at Jan. 31, 2015					14,857,582
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	$ 2,084,000		2,084,000
Proceeds from issuance of employee stock purchase plan shares	348,000	$ 2,000	346,000
Proceeds from issuance of employee stock purchase plan shares (in shares)		20,131
Common stock issued for net settlement of stock-based awards	(73,000)	$ 1,000	(74,000)
Common stock issued for net settlement of stock-based awards (in shares)		9,925
Cash dividends declared	(9,692,000)			(9,692,000)
Accrual of dividend equivalents, net of reversal	(41,000)			(41,000)
Net income tax shortfall from settlement of stock-based awards	(43,000)		(43,000)
Reversal of deferred tax assets associated with expired and unexercised stock-based awards	(35,000)		(35,000)
Net income	3,915,000			3,915,000
Ending balance at Jan. 31, 2016	$ 397,872,000	$ 3,120,000	$ 429,361,000	$ 407,240,000	$ (441,849,000)
Common stock, ending balance (in shares) at Jan. 31, 2016	31,195,457	31,195,457
Treasury stock, ending balance (in shares) at Jan. 31, 2016	15,033,317				15,033,317