Income Tax Expense (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Income Tax Expense [Line Items]
Accumulated unremitted earnings of foreign subsidiaries	$ 48,900
Accumulated unremitted earnings of foreign subsidiaries in cash	28,400
Income taxes due if foreign entities' earnings were distributed	6,900
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	100	$ 100
Capital loss carryforward, valuation allowance	400	600
Operating Loss Carryforwards, Valuation Allowance	400	300
Net operating loss carryforward - foreign	4,486	4,991
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	15,000
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	3,200
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	500
Deferred Tax Assets, Tax Credit Carryforwards, Research	2,100
State Research And Other Credit CarryForwards With Expiration Date	1,700
State Research And Other Credit Carry Forwards Without Expiration Date	400
Deferred Tax Assets, Valuation Allowance	4,440	5,711
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	1,300	1,600
FINLAND
Income Tax Expense [Line Items]
Deferred Tax Assets, Net	300
Deferred Tax Assets, Operating Loss Carryforwards	2,800
Brazil, Germany, India, Finland, China and the United Kingdom [Member]
Income Tax Expense [Line Items]
Net operating loss carryforward - foreign	18,200
Foreign Valuation Allowance [Member]
Income Tax Expense [Line Items]
Operating Loss Carryforwards, Valuation Allowance	$ 3,700	$ 4,800