Accounting Changes Accounting Changes (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Oct. 01, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax cuts and jobs act of 2017, reclassification from AOCI to retained earnings, tax effect	$ 5,451
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net periodic benefits expense (reversal of expense) excluding service cost component		$ 395	$ (644)	$ 807	$ (1,219)