Description of Business (Sale of Photovoltaics and Digital Products Business) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions			3 Months Ended								12 Months Ended
	Jun. 15, 2015	Dec. 10, 2014	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Apr. 17, 2015	Apr. 16, 2015	Jan. 02, 2015
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										$ 0	$ 0	$ 45,650
Repurchase costs	$ 700
Cash and cash equivalents			$ 68,333				$ 63,905				68,333	63,905
Working capital			103,000								103,000
Net income			$ 2,205	$ 2,425	$ 1,848	$ 1,757	$ 1,996	$ 1,301	$ 3,982	$ 987	$ 8,235	$ 8,266	63,100
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
Discontinued Operations, Disposed of by Sale [Member] | 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													149,900
Working capital adjustment		$ 100
Discontinued Operations, Disposed of by Sale [Member] | Digital Products Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset purchase agreement, selling price													$ 17,500
Asset sale, promissory note, principal amount, post-adjustment														$ 15,500	$ 15,500	$ 1,500
Asset sale, promissory note, principal amount, pre-adjustment																$ 16,000
Accrued interest on note receivable														$ 200