Revenue Recognition (Schedule of Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 28, 2019	Jun. 29, 2018	Jun. 28, 2019	Jun. 29, 2018
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 302,159	$ 214,780	$ 942,793	$ 814,029
Revenue from contract with customer, percent	100.00%	100.00%	100.00%	100.00%
United States
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 78,590	$ 63,691	$ 356,389	$ 268,505
Revenue from contract with customer, percent	26.00%	30.00%	38.00%	33.00%
International
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 223,569	$ 151,089
Revenue from contract with customer, percent	74.00%	70.00%	62.00%	67.00%
International
Revenue from External Customer [Line Items]
Revenue from contract with customer			$ 586,404	$ 545,524
Licensing
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 271,897	$ 183,771	$ 842,484	$ 726,078
Revenue from contract with customer, licensing percent	100.00%	100.00%	100.00%	100.00%
Revenue from contract with customer, percent	90.00%	86.00%	89.00%	89.00%
Products and services
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 30,262	$ 31,009	$ 100,309	$ 87,951
Revenue from contract with customer, percent	10.00%	14.00%	11.00%	11.00%
Broadcast
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 134,106	$ 83,760	$ 356,668	$ 283,027
Revenue from contract with customer, licensing percent	49.00%	46.00%	42.00%	39.00%
PC
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 24,579	$ 16,530	$ 88,929	$ 80,786
Revenue from contract with customer, licensing percent	9.00%	9.00%	11.00%	11.00%
Mobile
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 47,034	$ 19,596	$ 147,966	$ 146,473
Revenue from contract with customer, licensing percent	17.00%	11.00%	18.00%	20.00%
CE
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 28,662	$ 27,935	$ 117,188	$ 103,645
Revenue from contract with customer, licensing percent	11.00%	15.00%	14.00%	14.00%
Other
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 37,516	$ 35,950	$ 131,733	$ 112,147
Revenue from contract with customer, licensing percent	14.00%	19.00%	15.00%	16.00%