Marketable Securities Narrative (Details) - USD ($)	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Marketable securities sold during period, fair value	$ 0	$ 124,000,000
Marketable securities sold during period, amortized cost basis		124,200,000
Net realized losses		100,000
Proceeds from sale of marketable securities		123,500,000
Reclassification unrealized net holding losses		$ 100,000
Fair value of marketable securities	$ 3,700,000		$ 2,500,000