Joint Venture (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Oct. 01, 2018	Sep. 30, 2018	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity interest in earnings (losses) of joint venture	$ 1,465	$ 596
Costs recognized to fulfill a contract	92,091
ASC 606 [Member]
Schedule of Equity Method Investments [Line Items]
Revenue recognized to contract liabilities	4,428		$ 57,529
Costs recognized to fulfill a contract	$ 4,428		$ 57,529
Woodward and General Electric Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Agreement to Form Joint Venture, Execution Date	Jan. 04, 2016
Ownership interest, joint venture	50.00%				50.00%
Cash received from formation of joint venture	$ 250,000
Cash received annually from formation of joint venture	4,894
Current portion of deferred income recorded in connection with joint venture	6,988			$ 7,087
Noncurrent portion of deferred income recorded in connection with joint venture	232,897			235,300
Equity interest in earnings (losses) of joint venture	1,465	596
Cash distributions from joint venture	4,500	0
Net investment in joint venture	6,576			9,611
Accounts receivable from related party	6,916			10,499
Accounts payable to related party	3,063			$ 2,944
Woodward and General Electric Joint Venture [Member] | Sales [Member]
Schedule of Equity Method Investments [Line Items]
Amortization of deferred income recognized as an increase to sales	1,777	1,053
Sales to related party	12,833	12,975
Reduction to sales related to royalties paid to joint venture	$ 9,182	$ 5,408