Joint Ventures (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016	Jan. 04, 2016
Cash received from formation of joint venture			$ 0	$ 250,000
Current portion of deferred income recorded in connection with joint venture	$ 6,352		6,352		$ 6,552
Noncurrent portion of deferred income recorded in connection with joint venture	240,153		240,153		238,187
Income taxes payable	3,046		3,046		4,547
Equity interest in earnings of joint venture	$ 382	$ 2,158	$ 1,066	2,158
Woodward and General Electric Joint Venture [Member]
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Cash received from formation of joint venture		$ 250,000
Cash to be received annually from formation of joint venture	$ 4,894
Amount of deferred income recorded in connection with joint venture						$ 250,000
Current portion of deferred income recorded in connection with joint venture	6,352		$ 6,352		6,552
Noncurrent portion of deferred income recorded in connection with joint venture	240,153		240,153		238,187
Equity interest in earnings of joint venture	382		1,066	2,158
Cash distributions from joint venture			2,500	0
Net investment in joint venture	4,770		4,770		6,204
Accounts receivable from related party	8,816		8,816		5,326
Accounts payable to related party	7,019		7,019		$ 3,926
Woodward and General Electric Joint Venture [Member] | Sales [Member]
Amortization of deferred income recognized as an increase to sales	1,632		3,128	1,962
Sales to related party	18,415		33,717	15,015
Reduction to sales related to royalties paid to joint venture	$ 5,674		$ 11,077	$ 7,016