Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Sep. 30, 2020			55,303
Beginning Balance at Sep. 30, 2020	$ 649,127		$ 551	$ 398,475		$ 318,169		$ (68,068)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation	524			524
Release of restricted stock (in shares)			296
Release of restricted stock	5		$ 5
Taxes paid related to net share settlement of equity awards	(730)			(730)
Foreign currency translation gain (loss)	11,277							11,277
Net income	4,299					4,299
Ending Balance (in shares) at Dec. 31, 2020			55,599
Ending Balance at Dec. 31, 2020	664,502		$ 556	398,269		322,468		(56,791)
Beginning Balance (in shares) at Sep. 30, 2020			55,303
Beginning Balance at Sep. 30, 2020	649,127		$ 551	398,475		318,169		(68,068)
Ending Balance (in shares) at Sep. 30, 2021			56,057
Ending Balance at Sep. 30, 2021	$ 672,238	$ (37,406)	$ 560	403,312	$ (64,263)	326,781	$ 26,857	(58,415)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2020-06
Beginning Balance (in shares) at Dec. 31, 2020			55,599
Beginning Balance at Dec. 31, 2020	$ 664,502		$ 556	398,269		322,468		(56,791)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation	1,094			1,094
Transfer of consideration for prior period acquisition (in shares)			33
Transfer of consideration for prior period acquisition	185			185
Release of restricted stock (in shares)			212
Release of restricted stock	2		$ 2
Taxes paid related to net share settlement of equity awards	(109)			(109)
Foreign currency translation gain (loss)	(1,760)							(1,760)
Net income	5,330					5,330
Ending Balance (in shares) at Mar. 31, 2021			55,844
Ending Balance at Mar. 31, 2021	669,244		$ 558	399,439		327,798		(58,551)
Beginning Balance (in shares) at Sep. 30, 2021			56,057
Beginning Balance at Sep. 30, 2021	672,238	(37,406)	$ 560	403,312	(64,263)	326,781	26,857	(58,415)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation	1,698			1,698
Release of restricted stock (in shares)			257
Release of restricted stock	3		$ 3
Taxes paid related to net share settlement of equity awards	(792)			(792)
Foreign currency translation gain (loss)	3,039							3,039
Net income	15,721					15,721
Ending Balance (in shares) at Dec. 31, 2021			56,314
Ending Balance at Dec. 31, 2021	654,501		$ 563	339,955		369,359		(55,376)
Beginning Balance (in shares) at Sep. 30, 2021			56,057
Beginning Balance at Sep. 30, 2021	672,238	$ (37,406)	$ 560	403,312	$ (64,263)	326,781	$ 26,857	(58,415)
Ending Balance (in shares) at Mar. 31, 2022			56,656
Ending Balance at Mar. 31, 2022	675,016		$ 567	341,913		384,246		(51,710)
Beginning Balance (in shares) at Dec. 31, 2021			56,314
Beginning Balance at Dec. 31, 2021	654,501		$ 563	339,955		369,359		(55,376)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock compensation	460			460
Transfer of consideration for other investment (in shares)			213
Transfer of consideration for other investment	1,500		$ 2	1,498
Release of restricted stock (in shares)			129
Release of restricted stock	2		$ 2
Foreign currency translation gain (loss)	3,666							3,666
Net income	14,887					14,887
Ending Balance (in shares) at Mar. 31, 2022			56,656
Ending Balance at Mar. 31, 2022	$ 675,016		$ 567	$ 341,913		$ 384,246		$ (51,710)