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, 2021	Jun. 27, 2020	Jun. 30, 2021	Jun. 27, 2020
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	$ 435,668	$ 351,721	$ 1,326,504	$ 1,067,434
Operating costs	95,077	79,224	271,355	249,656
Gross margin	340,591	272,497	1,055,149	817,778
Sales and marketing	134,412	104,594	388,315	319,636
General and administrative	47,084	35,709	157,417	113,895
Restructuring and other charges, net	(132)	62	584	32,338
Intangibles amortization	15,771	14,159	43,352	41,902
Operating income	73,582	63,401	265,611	143,851
Interest and debt premium expense	(13,178)	(19,660)	(37,622)	(64,376)
Other income (expense), net	(1,935)	775	(5,756)	(150)
Income before income taxes	58,469	44,516	222,233	79,325
Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	435,668	351,721	1,326,504	1,067,434
Operating costs	151,343	125,048	432,313	389,324
Gross margin	284,325	226,673	894,191	678,110
Unallocated
Segment Reporting Revenue Reconciling Item [Line Items]
Sales and marketing	120,183	95,187	345,782	295,631
General and administrative	31,235	28,005	90,122	82,719
Restructuring and other charges, net	(132)	62	584	32,338
Intangibles amortization	15,771	14,159	43,352	41,902
Stock-based compensation	43,068	25,185	133,896	73,605
Other unallocated operating expenses	618	674	14,844	8,064
Software Products | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	394,434	317,394	1,209,622	955,840
Operating costs	116,617	95,198	331,328	292,302
Gross margin	277,817	222,196	878,294	663,538
Professional Services | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Revenue	41,234	34,327	116,882	111,594
Operating costs	34,726	29,850	100,985	97,022
Gross margin	$ 6,508	$ 4,477	$ 15,897	$ 14,572