Revenue (Significant Changes in Contact Assets and Liabilities) (Details) $ in Thousands	6 Months Ended
	Mar. 28, 2020 USD ($)
Contract Assets
Balance, September 28, 2019	$ 80,331
Changes in estimated stage of completion	60,450
Transfers to accounts receivable, net	(63,019)
Acquisitions	6,107
Other	(1,595)
Balance, March 28, 2020	82,274
Contract Liabilities
Balance, September 28, 2019	81,045
Revenue recognized included in balance at beginning of period	(46,899)
Increases due to payments received, excluding amounts recognized as revenue during period	36,061
Acquisitions	3,182
Other	(1,708)
Balance, March 28, 2020	$ 71,681