Operating Segments and Geographic Data (Revenue By Geographic Region) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 27, 2013	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	$ 232,748	$ 231,702	$ 271,950	$ 234,238	$ 226,957	$ 223,350	$ 278,592	$ 231,277	$ 970,638	$ 960,176	$ 909,674
U.S. [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue									276,733	316,256	255,956
International [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue									$ 693,905	$ 643,920	$ 653,718