Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Currency translation adjustments		$ 112	$ (96)	$ 64
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year		3,938	3,776	2,540
Additions: Charged to Costs and Expenses		4,899	207	1,063
Additions: Charged to Other Accounts	[1]	251	466	449
Deductions	[2]	(1,180)	(511)	(276)
Balance at End of Year		7,908	3,938	3,776
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year		4,522	3,714	3,317
Additions: Charged to Costs and Expenses		19	73	77
Additions: Charged to Other Accounts	[1]		553
Deductions	[2]	(903)	182	320
Balance at End of Year		$ 3,638	$ 4,522	$ 3,714

[1] Includes recoveries of accounts previously written off.

[2] Represents accounts receivable written off against the allowance for uncollectible accounts and releases of valuation reserves to income tax expense. Also included are foreign currency exchange rate adjustments. Currency translation adjustments resulted in a increase in the reserves of $112 in fiscal year 2019, an increase in the reserves of $96 in fiscal year 2018, and an increase in the reserves of $64 in fiscal year 2017.