Goodwill and Intangible Assets (Amortization of Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 7,821	$ 8,067
Cost of license and subscription revenue	6,675	6,388
Total amortization expense	$ 14,496	$ 14,455