Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended						12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Tax Credit Carryforward [Line Items]
U.S. capital loss carryforward	$ 5,500						$ 5,500
Valuation allowance	5,952			$ 5,970			5,952	$ 5,970
Net tax benefits	200	$ 700	$ 100	200	$ 500	$ 700	1,000	1,500	$ 800
Accrued income tax penalties and interest for unrecognized tax benefits	100			$ 200			100	$ 200
Accumulated undistributed foreign earnings	34,600						34,600
Maximum
Tax Credit Carryforward [Line Items]
Estimated unrecognized deferred tax liability	600						600
United States Federal Tax Jurisdiction
Tax Credit Carryforward [Line Items]
Federal and state research and development tax credits	2,000						2,000
U.S. capital loss carryforward	5,100						5,100
Foreign Tax Authority
Tax Credit Carryforward [Line Items]
Non-U.S. operating losses	$ 400						$ 400