CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	COMMON STOCK	CAPITAL IN EXCESS OF PAR VALUE	RETAINED EARNINGS	TREASURY SHARES	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	DEFERRED COMPENSATION	Series of Individually Immaterial Business Acquisitions	Series of Individually Immaterial Business Acquisitions CAPITAL IN EXCESS OF PAR VALUE	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment RETAINED EARNINGS
Balance (in shares) at Sep. 30, 2018		81,520,000			35,846,000
Balance at Sep. 30, 2018	$ 474,391	$ 20,380	$ 503,396	$ 550,523	$ (534,830)	$ (34,112)	$ (30,966)			$ (5,618)	$ (5,618)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 37,287			37,287
Accounting Standards Update [Extensible List]	Accounting Standards Update 2014-09 [Member]
Dividends	$ (13,676)			(13,676)
Shares withheld on employee taxes on vested equity awards (in shares)					86,000
Shares withheld on employee taxes on vested equity awards	(1,106)				$ (1,106)
Amortization of deferred compensation	2,726						2,726
Common stock acquired (in shares)					37,000
Common stock acquired	(372)				$ (372)
Equity awards granted, net (in shares)		1,255,000
Equity awards granted, net		$ 314	(314)
ESOP allocation of common stock	1,512		1,512
Stock-based compensation	13,285		13,285					$ 1,138	$ 1,138
Other comprehensive loss, net of tax	(31,804)					(31,804)
Balance (in shares) at Sep. 30, 2019		82,775,000			35,969,000
Balance at Sep. 30, 2019	477,763	$ 20,694	$ 519,017	568,516	$ (536,308)	(65,916)	(28,240)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	53,429			53,429
Dividends	(14,427)			(14,427)
Shares withheld on employee taxes on vested equity awards (in shares)					341,000
Shares withheld on employee taxes on vested equity awards	(7,479)				$ (7,479)
Amortization of deferred compensation	2,515						2,515
Common stock issued (in shares)			46,900,000		(8,700,000)
Common stock issued	177,194				$ 130,294
Equity awards granted, net (in shares)		964,000
Equity awards granted, net		$ 241	$ (241)
ESOP allocation of common stock	1,985		1,985
Stock-based compensation	14,702		14,702					$ 645	$ 645
Other comprehensive loss, net of tax	(6,176)					(6,176)
Balance (in shares) at Sep. 30, 2020		83,739,000			27,610,000
Balance at Sep. 30, 2020	700,151	$ 20,935	583,008	607,518	$ (413,493)	(72,092)	(25,725)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	79,211			79,211
Dividends	$ (16,731)			(16,731)
Shares withheld on employee taxes on vested equity awards (in shares)	152,435				152,000
Shares withheld on employee taxes on vested equity awards	$ (3,357)				$ (3,357)
Amortization of deferred compensation	2,437						2,437
Equity awards granted, net (in shares)		636,000
Equity awards granted, net		$ 159	(159)
ESOP allocation of common stock	2,922		2,922
Stock-based compensation	16,410		16,410
Other comprehensive loss, net of tax	26,115					26,115
Balance (in shares) at Sep. 30, 2021		84,375,000			27,762,000
Balance at Sep. 30, 2021	$ 807,158	$ 21,094	$ 602,181	$ 669,998	$ (416,850)	$ (45,977)	$ (23,288)