CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest in VIE	Total
Balance at Sep. 30, 2015	$ 25,560	$ 818,642	$ (51,836)	$ (36,078)
Balance (in shares) at Sep. 30, 2015	26,883
Increase (Decrease) in Stockholders' Equity
Net income (loss)		1,735				$ 1,735
Other comprehensive income (loss), net of tax			(67,981)			(67,981)
Stock issued under equity incentive plans, value		(57)
Stock issued under equity incentive plans, shares	152
Purchase of common stock, value	$ (1,563)
Purchase of common stock, shares	(43)
Stock- based compensation	$ 8,762
Tax benefit (expense) from equity incentive plans	(3)
Cash dividends paid		(7,285)
Balance at Sep. 30, 2016	$ 32,756	813,035	(119,817)	(36,078)
Balance (in shares) at Sep. 30, 2016	26,992
Increase (Decrease) in Stockholders' Equity
Net income (loss)		(11,209)				(11,209)
Other comprehensive income (loss), net of tax			13,191			13,191
Stock issued under equity incentive plans, shares	158
Stock issued under employee stock purchase plans, value	$ 2,234
Stock issued under employee stock purchase plans, shares	32
Purchase of common stock, value	$ (2,444)
Purchase of common stock, shares	(55)
Stock- based compensation	$ 5,269
Tax benefit (expense) from equity incentive plans	35
Cash dividends paid		(7,341)
Balance at Sep. 30, 2017	$ 37,850	794,485	(106,626)	(36,078)		689,631
Balance (in shares) at Sep. 30, 2017	27,127
Increase (Decrease) in Stockholders' Equity
Net income (loss)		12,310			$ (274)	12,310
Other comprehensive income (loss), net of tax			(1,623)			(1,623)
Stock issued under equity incentive plans, shares	158
Stock issued under employee stock purchase plans, value	$ 1,517
Stock issued under employee stock purchase plans, shares	26
Purchase of common stock, value	$ (2,449)
Purchase of common stock, shares	(56)
Stock- based compensation	$ 8,090
Equity contribution of noncontrolling interest					24,349
Cumulative effect of accounting standard adoption		2,394	(2,394)
Cash dividends paid		(7,355)
Balance at Sep. 30, 2018	$ 45,008	$ 801,834	$ (110,643)	$ (36,078)	$ 24,075	$ 724,196
Balance (in shares) at Sep. 30, 2018	27,255