Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Contract Loss Reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 43,214	$ 32,543	$ 30,422
Additions charged to cost and expenses	32,685	40,774	29,469
Deductions	33,556	30,134	27,152
Foreign exchange impact and other	(85)	31	(196)
Balance at end of year	42,258	43,214	32,543
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	4,351	4,538	5,286
Additions charged to cost and expenses	2,213	1,291	1,594
Deductions	1,468	1,786	2,095
Foreign exchange impact and other	(137)	308	(247)
Balance at end of year	4,959	4,351	4,538
Inventory Valuation Reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	108,539	109,192	103,350
Additions charged to cost and expenses	33,569	12,661	24,183
Deductions	15,540	14,019	17,622
Foreign exchange impact and other	(1,252)	705	(719)
Balance at end of year	125,316	108,539	109,192
Valuation Allowance of Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	4,776	10,938	9,583
Additions charged to cost and expenses	10,499	895	2,981
Deductions	101	7,172	1,521
Foreign exchange impact and other	7	115	(105)
Balance at end of year	$ 15,181	$ 4,776	$ 10,938