CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Retained Earnings Cumulative effect of accounting standard adoption	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest in VIE	Total
Balance at Sep. 30, 2019	$ 274,472	$ (824)	$ 862,948	$ (139,693)	$ (36,078)	$ 18,919
Balance (in shares) at Sep. 30, 2019							31,178
Increase (Decrease) in Stockholders' Equity
Net income (loss)			(20,575)			3,990	$ (20,575)
Other comprehensive income, net of tax				9,344			$ 9,344
Stock issued under equity incentive plans (in shares)							149
Stock issued under employee stock purchase plans, value	1,169
Purchase of common stock, value	(3,621)
Purchase of common stock (in shares)							(53)
Share - based compensation	4,477
Balance at Dec. 31, 2019	276,497		841,549	(130,349)	(36,078)	22,909
Balance (in shares) at Dec. 31, 2019							31,274
Balance at Sep. 30, 2020	295,986		850,472	(149,603)	(36,078)	27,403	$ 988,180
Balance (in shares) at Sep. 30, 2020							31,329
Increase (Decrease) in Stockholders' Equity
Net income (loss)			(12,995)			5,717	$ (12,995)
Other comprehensive income, net of tax				11,307			$ 11,307
Stock issued under equity incentive plans (in shares)							547
Purchase of common stock, value	(3,010)
Purchase of common stock (in shares)							(66)
Share - based compensation	4,679
Balance at Dec. 31, 2020	$ 297,655		$ 837,477	$ (138,296)	$ (36,078)	$ 33,120	$ 993,878
Balance (in shares) at Dec. 31, 2020							31,810