Segment and Geographic Information and Significant Customers (Segment Results Along with Reconciliation of Segment Profit to Income Before Income Taxes) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Stranded Costs		$ 4,000		$ 12,900
Segment Revenues	$ 338,398	377,437	$ 1,125,968	1,133,696
Segment profit	104,922	121,131	360,123	358,986
Corporate expenses and other, net	(28,389)	(36,328)	(87,711)	(103,279)
Acquisition-related revenues	0	(625)	(301)	(1,317)
Stock-based compensation	(33,135)	(30,181)	(98,030)	(84,476)
Amortization of intangible assets	(18,280)	(19,933)	(55,893)	(61,636)
Business Combination, Acquisition Related Costs	(758)	(788)	(3,605)	(5,440)
Restructuring and other charges, net	(1,920)	(1,947)	(14,932)	(26,446)
Other expenses, net	(22,438)	(21,296)	(79,912)	(79,466)
Income (loss) before income taxes	2	10,033	19,739	(3,074)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Segment Revenues	0	(625)	(301)	(1,317)
Health Care Segment [Member]
Segment Reporting Information [Line Items]
Segment Revenues	199,863	227,866	694,792	704,135
segment revenue	199,863	228,384	694,792	704,911
Segment profit	62,885	79,343	227,838	244,239
Enterprise Segment [Member]
Segment Reporting Information [Line Items]
Segment Revenues	130,392	137,782	406,008	382,676
segment revenue	130,392	137,888	406,310	383,217
Segment profit	36,992	38,743	118,265	101,331
Other Segments [Member]
Segment Reporting Information [Line Items]
Segment Revenues	8,143	11,789	25,168	46,885
segment revenue	8,143	11,790	25,167	46,885
Segment profit	5,045	3,045	14,020	13,416
Operating Segments [Member]
Segment Reporting Information [Line Items]
segment revenue	$ 338,398	$ 378,062	$ 1,126,269	$ 1,135,013