Revenue (Narrative - Performance Obligations) (Details1) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Remaining performance obligation amount	$ 1,454,406	$ 1,527,437
Material Rights [Member]
Remaining performance obligation amount	$ 465,668
Material Rights [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-10-01
Period of remaining performance obligation, expected timing of satisfaction	1 year
Remaining performance obligation amount	$ 6,983
Remaining performance obligation, expected timing of satisfaction, year	2021
Maximum [Member] | Material Rights [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
Period of remaining performance obligation, expected timing of satisfaction	40 years
Aerospace [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-10-01
Period of remaining performance obligation, expected timing of satisfaction	2 years