Revenue (Narrative - Performance Obligations) (Details1) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Remaining performance obligation amount	$ 1,274,218	$ 1,454,406
Material Rights [Member]
Remaining performance obligation amount	$ 464,296	$ 465,668
Material Rights [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-10-01
Period of remaining performance obligation, expected timing of satisfaction	9 months
Remaining performance obligation amount	$ 8,952
Remaining performance obligation, expected timing of satisfaction, year	2021
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	1 year 9 months
Remaining performance obligation amount	$ 10,625
Remaining performance obligation, expected timing of satisfaction, year	2022
Aerospace [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Period of remaining performance obligation, expected timing of satisfaction	2 years
Maximum [Member] | Material Rights [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Period of remaining performance obligation, expected timing of satisfaction	40 years