Segment and Geographic Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 03, 2015 USD ($)	Jul. 04, 2015 USD ($)	Apr. 04, 2015 USD ($)	Dec. 27, 2014 USD ($)	Sep. 27, 2014 USD ($)	Jun. 28, 2014 USD ($)	Mar. 29, 2014 USD ($)	Dec. 28, 2013 USD ($)	Oct. 03, 2015 USD ($) customers	Sep. 27, 2014 USD ($)	Sep. 28, 2013 USD ($)
Segment Reporting Information [Line Items]
Number of Customers, Minimum Ten Percent of Net Sales | customers									1
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Net sales:	$ 209,622	$ 188,502	$ 203,721	$ 200,615	$ 205,344	$ 196,517	$ 199,222	$ 193,556	$ 802,460	$ 794,639	$ 810,126
Total income (loss) from operations									100,747	76,866	84,899
Other income (expense), net									(1,179)	2,353	(1,403)
Income before income taxes									99,568	79,219	83,496
Provision for income taxes									23,159	20,113	17,141
Net income	$ 27,302	$ 13,264	$ 18,413	$ 17,430	$ 19,097	$ 12,999	$ 15,307	$ 11,703	$ 76,409	$ 59,106	$ 66,355
Sales [Member] | Customer One [Member] | Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage									17.00%	13.00%	14.00%
Specialty Laser Systems
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Net sales:									$ 559,593	$ 565,552	$ 571,644
Total income (loss) from operations									133,506	117,947	115,931
Commercial Lasers and Components
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Net sales:									242,867	229,087	238,482
Total income (loss) from operations									9,127	2,688	12,411
Corporate and other
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]
Total income (loss) from operations									$ (41,886)	$ (43,769)	$ (43,443)