Summary of Significant Accounting Policies - Advertising Costs and AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Advertising Costs
Advertising costs	$ 6,000	$ 5,300	$ 7,200
Accumulated Other Comprehensive Income (loss)
Balance	216,002	316,983	314,879
Current-period other comprehensive (loss) income	(2,945)	(2,175)	(3,969)
Balance	162,611	216,002	316,983
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (loss)
Balance	(6,947)	(3,671)	(629)
Current-period other comprehensive (loss) income	(398)	(3,276)	(3,042)
Balance	(7,345)	(6,947)	(3,671)
Net Change Pension and Other Post Retirement Benefit Plans
Accumulated Other Comprehensive Income (loss)
Balance	1,321	220	1,147
Current-period other comprehensive (loss) income	(2,547)	1,101	(927)
Balance	(1,226)	1,321	220
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (loss)
Balance	(5,626)	(3,451)	518
Current-period other comprehensive (loss) income	(2,945)	(2,175)	(3,969)
Balance	$ (8,571)	$ (5,626)	$ (3,451)