Condensed Consolidated Statements of Cash Flows (USD $)	6 Months Ended
	Jan. 31, 2013	Jan. 31, 2012
Cash flows from operating activities:
Net income	$ 9,800,000	$ 18,422,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, plant and equipment	4,019,000	4,781,000
Amortization of intangible assets with finite lives	3,164,000	3,411,000
Amortization of stock-based compensation	1,551,000	1,909,000
Deferred financing costs	706,000	746,000
Change in fair value of contingent earn-out liability	(3,267,000)	0
Loss on disposal of property, plant and equipment	32,000	2,000
Benefit from allowance for doubtful accounts	(107,000)	(50,000)
Provision for excess and obsolete inventory	1,276,000	1,616,000
Excess income tax benefit from stock-based award exercises	(19,000)	(82,000)
Deferred income tax expense (benefit)	1,029,000	(1,953,000)
Changes in assets and liabilities:
Accounts receivable	14,113,000	9,949,000
Inventories	905,000	(5,007,000)
Prepaid expenses and other current assets	(740,000)	(255,000)
Other assets	15,000	(23,000)
Accounts payable	(6,899,000)	(4,833,000)
Accrued expenses and other current liabilities	(8,645,000)	(9,003,000)
Customer advances and deposits	(3,986,000)	(2,963,000)
Other liabilities	588,000	446,000
Interest payable	0	22,000
Income taxes payable	(2,141,000)	(5,935,000)
Net cash provided by operating activities	11,394,000	11,200,000
Cash flows from investing activities:
Purchases of property, plant and equipment	(2,457,000)	(2,660,000)
Net cash used in investing activities	(2,457,000)	(2,660,000)
Cash flows from financing activities:
Repurchases of common stock	(10,477,000)	(157,745,000)
Cash dividends paid	(14,335,000)	(12,202,000)
Proceeds from exercises of stock options	446,000	2,587,000
Proceeds from issuance of employee stock purchase plan shares	478,000	556,000
Excess income tax benefit from stock-based award exercises	19,000	82,000
Payment of contingent consideration related to business acquisition	(10,000)	(157,000)
Fees related to line of credit	(25,000)	(249,000)
Net cash used in financing activities	(23,904,000)	(167,128,000)
Net decrease in cash and cash equivalents	(14,967,000)	(158,588,000)
Cash and cash equivalents at beginning of period	367,894,000	558,804,000
Cash and cash equivalents at end of period	352,927,000	400,216,000
Cash paid during the period for:
Interest	3,177,000	3,193,000
Income taxes	7,070,000	12,481,000
Non cash investing and financing activities:
Cash dividends declared	$ 0	$ 5,352,000