Segment and Geographic Information - Summary of Revenue and Profit Attributable to Our Operating Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue		$ 465,910	$ 457,721
Operating costs		95,790	95,118
Gross margin		370,120	362,603
Sales and marketing expenses		118,383	125,476
General and administrative expenses		50,971	51,940
Restructuring and other charges (credits), net		(338)	33,991
Intangibles amortization		14,168	14,977
Operating income		104,901	62,178
Interest and debt premium expense		(16,358)	(12,986)
Other income (expense), net		(2,119)	6,184
Income before income taxes		86,424	55,376
Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue		465,910	457,721
Operating costs		162,292	153,011
Gross margin		303,618	304,710
Operating Segments | Software Products
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue		430,354	413,593
Operating costs	[1]	130,728	116,028
Gross margin		299,626	297,565
Operating Segments | Professional Services
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue		35,556	44,128
Operating costs	[2]	31,564	36,983
Gross margin		3,992	7,145
Unallocated
Segment Reporting Revenue Reconciling Item [Line Items]
Sales and marketing expenses		106,187	112,395
General and administrative expenses		31,390	34,177
Restructuring and other charges (credits), net		(338)	33,991
Intangibles amortization		14,168	14,977
Stock-based compensation		41,504	45,942
Other unallocated operating expenses	[3]	$ 5,806	$ 1,050

[1] Operating costs for the Software Products segment include all costs of software revenue and research and development costs, excluding stock-based compensation and intangible amortization.

[2] Operating costs for the Professional Services segment include all costs of professional services revenue, excluding stock-based compensation.

[3] Other unallocated operating expenses include acquisition and transaction-related costs.