Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Taxes [Line Items]
Net discrete impacts of the enactment of the Tax Act		$ 3,671	$ 14,778		$ 10,860
Transition Tax Liability Period Adjustment	$ 12,420
Tax expense benefit anticipated repatriation taxes, Tax Act	3,083
Net impact on U.S. deferred tax assets and liabilities	222
Adjustment to prior period items, Tax Act	1,526
Total Accrued Transition Tax Liability	13,580			$ 13,580	13,580
Current Accrued Transition Tax Liability	1,086			1,086	1,086
Noncurrent Accrued Transition Tax Liability	12,494			12,494	12,494
Noncurrent income taxes payable	12,494			$ 12,494	$ 12,494	$ 0
Statutory tax rate			35.00%	21.00%	24.50%	35.00%	35.00%
Income tax expense (benefit) adjustments due to resolution of prior years' tax issues					$ 6,677
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	6,071			$ 6,071	6,071	$ 4,707
Undistributed foreign earnings for which Woodward has not provided for taxes	199,845			199,845	199,845
Unrecognized Tax Benefits	8,364			8,364	8,364	20,132	$ 23,526	$ 21,469
Unrecognized tax benefits that, if recognized, would affect the effective tax rate	3,288			3,288	3,288	9,677
Accrued interest and penalties	$ 279			$ 279	$ 279	$ 1,273
Scenario, Forecast [Member]
Income Taxes [Line Items]
Statutory tax rate					21.00%