Description of Business (Liquidity and Capital Resources) (Details) - USD ($) $ / shares in Units, shares in Millions		3 Months Ended		9 Months Ended
	Jun. 15, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jul. 05, 2016	Sep. 30, 2015	Dec. 10, 2014	Sep. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shares acquired (in shares)	6.9
Average cost per share (in usd per share)	$ 6.55
Repurchases of common stock	$ 45,000,000			$ 0	$ 45,618,000
Repurchase costs	$ 700,000
Cash and cash equivalents		$ 105,046,000	$ 114,129,000	105,046,000	114,129,000		$ 111,885,000		$ 20,687,000
Working capital		129,900,000		129,900,000
Net income		1,301,000	$ 2,440,000	6,270,000	$ 61,620,000
Photovoltaics Business [Member] | Photovoltaics [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset purchase agreement, selling price								$ 150,000,000
Sixth Amendment [Member] | Revolving Credit Facility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Line of credit facility, maximum borrowing capacity								$ 15,000,000.00
Subsequent Event [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Dividends payable (in usd per share)						$ 1.50
Dividends payable						$ 39,200,000
Sumitomo Electric Industries, LTD [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Recovery of fees and costs from SEI		2,600,000		2,600,000
Receivable in escrow		$ 1,900,000		$ 1,900,000