Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Contract Loss Reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 48,818	$ 46,314	$ 36,793
Additions charged to cost and expenses	45,464	36,830	43,874
Deductions	35,714	34,241	34,384
Foreign exchange impact and other	2,346	(85)	31
Balance at end of year	60,914	48,818	46,314
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	4,959	4,351	4,538
Additions charged to cost and expenses	1,522	2,213	1,291
Deductions	891	1,468	1,786
Foreign exchange impact and other	(188)	(137)	308
Balance at end of year	5,402	4,959	4,351
Inventory Valuation Reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	125,316	108,539	109,192
Additions charged to cost and expenses	23,227	33,569	12,661
Deductions	12,716	15,540	14,019
Foreign exchange impact and other	(1,642)	(1,252)	705
Balance at end of year	134,185	125,316	108,539
Valuation Allowance of Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	15,181	4,776	10,938
Additions charged to cost and expenses	274	10,499	895
Deductions	1,808	101	7,172
Foreign exchange impact and other	(510)	7	115
Balance at end of year	$ 13,137	$ 15,181	$ 4,776