Reportable Segments - Operating Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 239,476	$ 228,552	$ 224,538	$ 225,589	$ 228,854	$ 217,268	$ 213,034	$ 212,766	$ 918,155	$ 871,922	$ 770,157
Income from operations									83,519	121,664	110,410
Interest expense, net									9,505	5,289	4,303
Other income									(1,305)	(1,138)	(126)
Income before income taxes									75,319	117,513	106,233
Identifiable assets	1,070,366				963,708				1,070,366	963,708
Capital expenditures									95,438	37,698	27,065
Depreciation and amortization									42,359	34,830	33,452
Operating Segment
Segment Reporting Information [Line Items]
Income from operations									146,119	161,020	142,753
General corporate
Segment Reporting Information [Line Items]
Income from operations									62,600	39,356	32,343
Identifiable assets	62,054				88,101				62,054	88,101
Capital expenditures									6,677	11,208	5,772
Depreciation and amortization									1,961	733	518
Medical
Segment Reporting Information [Line Items]
Net sales									523,669	473,937	398,773
Medical | Operating Segment
Segment Reporting Information [Line Items]
Income from operations									98,356	86,833	73,440
Identifiable assets	532,250				490,702				532,250	490,702
Capital expenditures									52,907	18,996	13,816
Depreciation and amortization									23,033	19,002	18,245
Life Sciences
Segment Reporting Information [Line Items]
Net sales									201,022	217,030	196,446
Life Sciences | Operating Segment
Segment Reporting Information [Line Items]
Income from operations									20,552	36,803	33,159
Identifiable assets	184,737				151,460				184,737	151,460
Capital expenditures									16,408	4,409	3,689
Depreciation and amortization									7,482	5,628	5,706
Dental
Segment Reporting Information [Line Items]
Net sales									161,608	149,360	144,457
Dental | Operating Segment
Segment Reporting Information [Line Items]
Income from operations									22,289	30,004	28,000
Identifiable assets	272,309				210,831				272,309	210,831
Capital expenditures									16,243	2,441	2,492
Depreciation and amortization									9,844	8,756	8,556
Dialysis
Segment Reporting Information [Line Items]
Net sales									31,856	31,595	30,481
Dialysis | Operating Segment
Segment Reporting Information [Line Items]
Income from operations									4,922	7,380	8,154
Identifiable assets	$ 19,016				$ 22,614				19,016	22,614
Capital expenditures									3,203	644	1,296
Depreciation and amortization									$ 39	711	$ 427
Restatement Adjustment | Life Sciences
Segment Reporting Information [Line Items]
Net sales										5,820
Income from operations										1,704
Restatement Adjustment | Dental
Segment Reporting Information [Line Items]
Net sales										(5,820)
Income from operations										$ (1,704)