Income Taxes (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended			21 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Jun. 30, 2019	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2019
Income Taxes [Line Items]
Statutory tax rate	21.00%	35.00%			21.00%	24.50%	35.00%	21.00%
Net discrete impacts of the enactment of the Tax Act			$ 10,588	$ 14,778		$ 10,860
Undistributed foreign earnings not provided for taxes					$ 293,538			$ 293,538
Unrecognized tax benefits that, if recognized, would affect the effective tax rate					4,411	3,288		4,411
Accrued interest and penalties					437	279		437
Net operating loss deferred tax asset, foreign					$ 6,836	$ 6,071		$ 6,836
Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Years remaining open to tax examination					2017
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Years remaining open to tax examination					2017
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Years remaining open to tax examination					2015
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Years remaining open to tax examination					2016