Revenue Recognition (Schedule of Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 25, 2021	Jun. 26, 2020	Jun. 25, 2021	Jun. 26, 2020
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 286,799	$ 246,909	$ 996,231	$ 890,601
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	$ 73,355	$ 72,261	$ 327,696	$ 366,474
Revenue from contract with customer, percent	26.00%	29.00%	33.00%	41.00%
International
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 213,444	$ 174,648	$ 668,535	$ 524,127
Revenue from contract with customer, percent	74.00%	71.00%	67.00%	59.00%
Licensing
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 271,569	$ 235,125	$ 948,159	$ 821,673
Revenue from contract with customer, licensing percent	100.00%	100.00%	100.00%	100.00%
Revenue from contract with customer, percent	95.00%	95.00%	95.00%	92.00%
Products and services
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 15,230	$ 11,784	$ 48,072	$ 68,928
Revenue from contract with customer, percent	5.00%	5.00%	5.00%	8.00%
Broadcast
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 123,955	$ 88,824	$ 368,068	$ 319,634
Revenue from contract with customer, licensing percent	46.00%	38.00%	39.00%	39.00%
PC
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 24,870	$ 23,537	$ 108,709	$ 101,171
Revenue from contract with customer, licensing percent	9.00%	10.00%	11.00%	12.00%
Mobile
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 49,861	$ 77,641	$ 221,157	$ 187,819
Revenue from contract with customer, licensing percent	18.00%	33.00%	23.00%	23.00%
CE
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 37,805	$ 20,365	$ 138,010	$ 118,409
Revenue from contract with customer, licensing percent	14.00%	9.00%	15.00%	14.00%
Other
Revenue from External Customer [Line Items]
Revenue from contract with customer	$ 35,078	$ 24,758	$ 112,215	$ 94,640
Revenue from contract with customer, licensing percent	13.00%	10.00%	12.00%	12.00%