CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Cash flows from operating activities
Net income	$ 47,953,000	$ 43,265,000	$ 39,239,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	10,692,000	8,245,000	7,202,000
Amortization	13,265,000	10,641,000	10,061,000
Stock-based compensation expense	5,867,000	5,409,000	3,733,000
Amortization of debt issuance costs	401,000	440,000	345,000
Loss on disposal of fixed assets	360,000	501,000	184,000
Loss on sale of business	2,206,000
Impairment of assets	1,287,000
Fair value adjustments to acquisition related liabilities	(2,585,000)	219,000	(2,492,000)
Deferred income taxes	(1,449,000)	(1,218,000)	(368,000)
Excess tax benefits from stock-based compensation	(3,168,000)	(4,391,000)	(2,875,000)
Changes in assets and liabilities, net of effects of business acquisitions/divestiture:
Accounts receivable	(3,905,000)	(6,149,000)	(2,447,000)
Inventories, net	(10,075,000)	(2,658,000)	(5,262,000)
Prepaid expenses and other current assets	(2,996,000)	(2,388,000)	(1,387,000)
Accounts payable and other current liabilities	(3,347,000)	6,205,000	931,000
Income taxes	4,564,000	6,151,000	4,630,000
Net cash provided by operating activities	59,070,000	64,272,000	51,494,000
Cash flows from investing activities
Capital expenditures	(12,760,000)	(13,541,000)	(6,745,000)
Proceeds from disposal of fixed assets	25,000	14,000	32,000
Proceeds from sale of business, net of cash retained and disposal costs	3,767,000
Acquisition of DentaPure, net of cash acquired	(9,957,000)
Acquisition of Pure Water Solutions	(11,835,000)
Acquisition of IMS, net of cash acquired	(22,112,000)
Acquisition of PuriCore, net of cash acquired	337,000	(25,386,000)
Acquisition of Sterilator, net of cash acquired		(2,829,000)
Acquisition of Jet Prep, net of cash acquired		(5,332,000)
Acquisition of Siemens Water			(8,300,000)
Acquisition of Eagle Pure Water			(870,000)
Acquisition of Polyp Trap			(486,000)
Acquisition of SPS, net of cash acquired			(35,415,000)
Other, net	241,000	(358,000)	(262,000)
Net cash used in investing activities	(52,294,000)	(47,432,000)	(52,046,000)
Cash flows from financing activities
Borrowings under revolving credit facility	47,000,000	28,000,000	45,000,000
Repayments under term loan facility		(5,000,000)	(10,000,000)
Repayments under revolving credit facility	(49,000,000)	(37,500,000)	(30,000,000)
Debt modification costs		(1,314,000)
Proceeds from exercises of stock options	608,000	634,000	1,817,000
Dividends paid	(4,154,000)	(3,721,000)	(3,016,000)
Excess tax benefits from stock-based compensation	3,168,000	4,391,000	2,875,000
Purchases of treasury stock	(3,727,000)	(4,439,000)	(2,252,000)
Net cash (used in) provided by financing activities	(6,105,000)	(18,949,000)	4,424,000
Effect of exchange rate changes on cash and cash equivalents	(732,000)	(186,000)	18,000
(Decrease) increase in cash and cash equivalents	(61,000)	(2,295,000)	3,890,000
Cash and cash equivalents at beginning of year	31,781,000	34,076,000	30,186,000
Cash and cash equivalents at end of year	$ 31,720,000	$ 31,781,000	$ 34,076,000