Income Taxes (Tax Expense and Effective Tax Rate) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Taxes
Earnings before income taxes	$ 37,487	$ 47,059
Income tax expense	$ 19,227	$ 511
Effective tax rate	51.30%	1.10%