Marketable Securities Narrative (Details) - USD ($)	3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Marketable securities sold during period, fair value	$ 3,500,000	$ 127,600,000
Marketable securities sold during period, amortized cost basis		127,700,000
Gross realized losses	17,000	158,000
Gross realized gains		3,000
Proceeds from sale of marketable securities	3,500,000	127,000,000
Change in net unrealized holding gain (loss) included in AOCI	17,000	155,000
Gross unrealized gains		22,000	$ 202,000	$ 102,300
Fair value of marketable securities	$ 2,000,000	$ 2,000,000		$ 40,400,000