Segment and Geographic Information - Summary of Revenue and Profit Attributable to Our Operating Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	$ 1,933,347	$ 1,807,159	$ 1,458,415
Operating costs	385,980	371,102	334,271
Gross margin	1,547,367	1,436,057	1,124,144
Sales and marketing	485,247	517,779	435,451
General and administrative	204,732	206,006	159,826
Intangibles amortization	60,548	59,165	56,104
Restructuring and other charges, net	36,234	2,211	32,716
Total operating income	447,362	380,748	210,863
Interest expense	(54,268)	(50,478)	(76,428)
Other income, net	4,004	61,485	271
Income before income taxes	397,098	391,755	134,706
Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	1,933,347	1,807,159	1,458,415
Operating costs	634,505	587,715	522,481
Gross margin	1,298,842	1,219,444	935,934
Operating Segments | Software Products
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	1,770,253	1,649,341	1,314,617
Operating costs	494,035	451,734	393,803
Gross margin	1,276,218	1,197,607	920,814
Operating Segments | Professional Services
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	163,094	157,818	143,798
Operating costs	140,470	135,981	128,678
Gross margin	22,624	21,837	15,120
Unallocated
Segment Reporting Revenue Reconciling Item [Line Items]
Sales and marketing	435,780	464,067	398,100
General and administrative	130,870	120,954	114,386
Intangibles amortization	60,548	59,165	56,104
Restructuring and other charges, net	36,234	2,211	32,716
Stock-based compensation	174,863	177,289	115,149
Other unallocated operating expenses	$ 13,185	$ 15,010	$ 8,616