Segment and Geographic Information - Summary of Revenue and Profit Attributable to Our Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	$ 462,474	$ 435,668	$ 1,425,422	$ 1,326,504
Operating costs	101,995	95,077	290,450	271,355
Gross margin	360,479	340,591	1,134,972	1,055,149
Sales and marketing	124,325	134,412	366,209	388,315
General and administrative	54,618	47,084	154,027	157,417
Restructuring and other charges, net	4,458	(132)	36,887	584
Intangibles amortization	15,527	15,771	44,875	43,352
Operating income	79,977	73,582	301,345	265,611
Interest and debt premium expense	(13,758)	(13,178)	(38,983)	(37,622)
Other income (expense), net	34,559	(1,935)	(2,642)	(5,756)
Income before income taxes	100,778	58,469	259,720	222,233
Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	462,474	435,668	1,425,422	1,326,504
Operating costs	164,138	151,343	472,732	432,313
Gross margin	298,336	284,325	952,690	894,191
Unallocated
Segment Reporting Revenue Reconciling Item [Line Items]
Sales and marketing	110,296	120,183	327,653	345,782
General and administrative	32,303	31,235	97,339	90,122
Restructuring and other charges, net	4,458	(132)	36,887	584
Intangibles amortization	15,527	15,771	44,875	43,352
Stock-based compensation	49,420	43,068	133,283	133,896
Other unallocated operating expenses	6,355	618	11,308	14,844
Software Products | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	423,400	394,434	1,299,243	1,209,622
Operating costs	127,964	116,617	365,008	331,328
Gross margin	295,436	277,817	934,235	878,294
Professional Services | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	39,074	41,234	126,179	116,882
Operating costs	36,174	34,726	107,724	100,985
Gross margin	$ 2,900	$ 6,508	$ 18,455	$ 15,897