Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Cash flows from operating activities:
Net income	$ 17,808,000	$ 32,416,000	$ 67,895,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, plant and equipment	7,837,000	10,205,000	14,253,000
Amortization of intangible assets with finite lives	6,328,000	6,637,000	8,091,000
Amortization of stock-based compensation	3,130,000	3,572,000	5,357,000
Deferred financing costs	1,419,000	1,652,000	1,391,000
Change in fair value of contingent earn-out liability	(3,267,000)	(918,000)	0
Loss on disposal of property, plant and equipment	9,000	14,000	7,000
(Benefit from) provision for allowance for doubtful accounts	(422,000)	458,000	244,000
Provision for excess and obsolete inventory	2,810,000	3,862,000	4,091,000
Excess income tax benefit from stock-based award exercises	(265,000)	(231,000)	(225,000)
Deferred income tax expense (benefit)	1,115,000	(4,570,000)	761,000
Changes in assets and liabilities, net of effects of acquisition:
Accounts receivable	6,591,000	14,101,000	64,795,000
Inventories	4,093,000	(4,407,000)	(5,224,000)
Prepaid expenses and other current assets	216,000	1,427,000	1,606,000
Other Assets	79,000	201,000	737,000
Accounts payable	(2,577,000)	(2,534,000)	(54,343,000)
Accrued expenses and other current liabilities	(9,484,000)	(5,221,000)	(4,866,000)
Customer advances and deposits	391,000	3,505,000	(1,927,000)
Other liabilities	735,000	877,000	789,000
Interest payable	0	(2,000)	0
Income taxes payable	1,149,000	(7,551,000)	(6,072,000)
Net cash provided by operating activities	37,695,000	53,493,000	97,360,000
Cash flows from investing activities:
Purchases of property, plant and equipment	(5,347,000)	(6,413,000)	(7,138,000)
Purchases of other intangibles with finite lives	0	0	(50,000)
Payments for business acquisitions	0	0	(2,850,000)
Net cash used in investing activities	(5,347,000)	(6,413,000)	(10,038,000)
Cash flows from financing activities:
Repurchases of common stock	(26,954,000)	(219,375,000)	(119,617,000)
Cash dividends paid	(18,879,000)	(22,625,000)	(20,135,000)
Proceeds from exercises of stock options	1,182,000	3,202,000	2,838,000
Proceeds from issuance of employee stock purchase plan shares	908,000	1,088,000	1,140,000
Excess income tax benefit from stock-based award exercises	265,000	231,000	225,000
Payment of contingent consideration related to business acquisition	(97,000)	(195,000)	(24,000)
Fees related to line of credit	(25,000)	(316,000)	(539,000)
Net cash used in financing activities	(43,600,000)	(237,990,000)	(136,112,000)
Net decrease in cash and cash equivalents	(11,252,000)	(190,910,000)	(48,790,000)
Cash and cash equivalents at beginning of period	367,894,000	558,804,000	607,594,000
Cash and cash equivalents at end of period	356,642,000	367,894,000	558,804,000
Cash paid during the period for:
Interest	6,350,000	6,509,000	6,407,000
Income taxes	7,420,000	23,746,000	39,498,000
Non cash investing and financing activities:
Business acquisition liabilities	0	0	4,170,000
Cash dividends declared	4,531,000	4,773,000	6,100,000
Accrued repurchases of common stock	$ 0	$ 0	$ 2,001,000