Valuation and Qualifying Accounts (Details) - Allowance For Doubtful Accounts Member - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period		$ 15,283	$ 23,992	$ 20,624
Charged to costs & expenses		10,397	15,082	19,491
Charged to other accounts		0	0	0
Valuation Allowances and Reserves, Deductions	[1]	12,313	23,791	16,123
Balance at end of period		$ 13,367	$ 15,283	$ 23,992

[1] Uncollectible accounts written off.