Schedule of Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014		Dec. 27, 2013	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 28, 2012	Sep. 26, 2014	Sep. 27, 2013	Sep. 28, 2012
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 812,100	$ 747,700	$ 778,500	[1]	$ 711,500	$ 769,900	$ 726,200	$ 768,400	$ 678,400	$ 3,049,800	$ 2,942,897	$ 2,807,015
Gross margin	340,100	323,700	328,300	[1]	309,600	328,500	310,500	319,600	291,100	1,301,675	1,249,687	1,196,336
Net earnings	$ 105,900	$ 107,100	$ 92,700	[1]	$ 98,000	$ 117,300	$ 112,800	$ 112,800	$ 95,300	$ 403,703	$ 438,248	$ 427,049
Net earnings per share – basic:	$ 1.04	$ 1.03	$ 0.89	[1]	$ 0.92	$ 1.09	$ 1.04	$ 1.04	$ 0.87	$ 3.88	$ 4.04	$ 3.83
Net earnings per share – diluted:	$ 1.02	$ 1.02	$ 0.88	[1]	$ 0.91	$ 1.08	$ 1.03	$ 1.02	$ 0.86	$ 3.83	$ 3.98	$ 3.76

[1] In the second fiscal quarter of 2014, net earnings include a $25.1 million litigation charge related to a settlement agreement with the University of Pittsburgh.