Revenue - Contract Balances (Details) - USD ($)	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Change In Contract With Customer, Assets [Roll Forward]
Contract assets - Beginning balance, October 1, 2018	$ 10,140,000	$ 0
Additional revenue recognized over-time	17,827,000	122,000	$ 0
Less amounts billed to the customers	(17,705,000)
Contract assets - Ending balance, December 31, 2018	10,262,000	10,262,000
Change In Contract With Customer, Liability [Roll Forward]
Contract liabilities (included within Accrued liabilities) - Beginning balance, October 1, 2018		0
Performance obligations satisfied		559,000
Payments received in advance of performance obligations		(1,000,000)
Contract liabilities (included within Accrued liabilities) - Ending balance, December 31, 2018	$ (441,000)	(441,000)
Impairment loss on contract assets		$ 0