Income Taxes (Tax Expense and Effective Tax Rate) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Income Taxes [Abstract]
Earnings before income taxes	$ 107,199	$ 90,168	$ 168,747	$ 151,683
Income tax expense	$ 15,881	$ 12,589	$ 24,056	$ 24,984
Effective tax rate	14.80%	14.00%	14.30%	16.50%

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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