Revenue (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019
Billed accounts receivable due within	60 days		60 days
Noncurrent unbilled receivables	$ 22,111		$ 22,111		$ 1,573
Revenue from contract liabilities	15,962	$ 10,552	19,932	$ 20,312
Remaining performance obligation amount	1,728,437		1,728,437		$ 1,527,437
Material Rights [Member]
Remaining performance obligation amount	$ 454,471		$ 454,471
Net Sales [Member] \| Manufactured Products [Member]
Percentage of attributable to revenue	86.00%	87.00%	86.00%	87.00%
Net Sales [Member] \| MRO Products [Member]
Percentage of attributable to revenue	13.00%	12.00%	12.00%	12.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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