CONDENSED CONSOLIDATED STATEMENT 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
Beginning balance (in shares) at Sep. 30, 2021		84,375,000
Beginning balance (in shares) at Sep. 30, 2021					27,762,000
Balance at Sep. 30, 2021	$ 807,158	$ 21,094	$ 602,181	$ 669,998	$ (416,850)	$ (45,977)	$ (23,288)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,298			19,298
Dividend	(4,739)			(4,739)
Shares withheld on employee taxes on vested equity awards (in shares)					422,000
Shares withheld on employee taxes on vested equity awards	(10,886)				$ (10,886)
Amortization of deferred compensation	591						591
Equity awards granted, net (in shares)		113,000			0
Equity awards granted, net		$ 28	(28)
ESOP allocation of common stock	848		848
Stock-based compensation	2,866		2,866
Other comprehensive income, net of tax	(2,751)					(2,751)
Ending balance (in shares) at Dec. 31, 2021		84,488,000
Ending balance (in shares) at Dec. 31, 2021					28,184,000
Balance at Dec. 31, 2021	812,385	$ 21,122	605,867	684,557	$ (427,736)	(48,728)	(22,697)
Beginning balance (in shares) at Sep. 30, 2021		84,375,000
Beginning balance (in shares) at Sep. 30, 2021					27,762,000
Balance at Sep. 30, 2021	807,158	$ 21,094	602,181	669,998	$ (416,850)	(45,977)	(23,288)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	225,274
Other comprehensive income, net of tax	(11,979)
Ending balance (in shares) at Jun. 30, 2022		84,746,000
Ending balance (in shares) at Jun. 30, 2022					27,682,000
Balance at Jun. 30, 2022	906,315	$ 21,187	609,027	775,694	$ (420,122)	(57,956)	(21,515)
Beginning balance (in shares) at Dec. 31, 2021		84,488,000
Beginning balance (in shares) at Dec. 31, 2021					28,184,000
Balance at Dec. 31, 2021	812,385	$ 21,122	605,867	684,557	$ (427,736)	(48,728)	(22,697)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	65,689			65,689
Dividend	(5,352)			(5,352)
Amortization of deferred compensation	591						591
Equity awards granted, net (in shares)		258,000			(470,000)
Equity awards granted, net		$ 65	(7,195)		$ 7,130
ESOP allocation of common stock	638		638
Stock-based compensation	4,314		4,314
Other comprehensive income, net of tax	4,949					4,949
Ending balance (in shares) at Mar. 31, 2022		84,746,000
Ending balance (in shares) at Mar. 31, 2022					27,714,000
Balance at Mar. 31, 2022	883,214	$ 21,187	603,624	744,894	$ (420,606)	(43,779)	(22,106)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	140,287			140,287
Dividend	(109,487)			(109,487)
Amortization of deferred compensation	591						591
Equity awards granted, net (in shares)		0			(32,000)
Equity awards granted, net		$ 0	(484)		$ 484
ESOP allocation of common stock	757		757
Stock-based compensation	5,130		5,130
Other comprehensive income, net of tax	(14,177)					(14,177)
Ending balance (in shares) at Jun. 30, 2022		84,746,000
Ending balance (in shares) at Jun. 30, 2022					27,682,000
Balance at Jun. 30, 2022	906,315	$ 21,187	609,027	775,694	$ (420,122)	(57,956)	(21,515)
Beginning balance (in shares) at Sep. 30, 2022		84,746,000
Beginning balance (in shares) at Sep. 30, 2022					27,682,000
Balance at Sep. 30, 2022	477,570	$ 21,187	627,982	344,060	$ (420,116)	(82,738)	(12,805)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	48,702			48,702
Dividend	(6,145)			(6,145)
Shares withheld on employee taxes on vested equity awards (in shares)					345,000
Shares withheld on employee taxes on vested equity awards	(12,734)				$ (12,734)
Amortization of deferred compensation	571						571
Equity awards granted, net (in shares)		0			(467,000)
Equity awards granted, net		$ 0	(7,082)		$ 7,082
ESOP allocation of common stock	1,127		1,127
Stock-based compensation	5,538		5,538
Other comprehensive income, net of tax	12,219					12,219
Ending balance (in shares) at Dec. 31, 2022		84,746,000
Ending balance (in shares) at Dec. 31, 2022					27,560,000
Balance at Dec. 31, 2022	526,848	$ 21,187	627,565	386,617	$ (425,768)	(70,519)	(12,234)
Beginning balance (in shares) at Sep. 30, 2022		84,746,000
Beginning balance (in shares) at Sep. 30, 2022					27,682,000
Balance at Sep. 30, 2022	477,570	$ 21,187	627,982	344,060	$ (420,116)	(82,738)	(12,805)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	35,652
Other comprehensive income, net of tax	15,147
Ending balance (in shares) at Jun. 30, 2023		84,746,000
Ending balance (in shares) at Jun. 30, 2023					30,083,000
Balance at Jun. 30, 2023	335,706	$ 21,187	652,166	246,392	$ (511,414)	(67,591)	(5,034)
Beginning balance (in shares) at Dec. 31, 2022		84,746,000
Beginning balance (in shares) at Dec. 31, 2022					27,560,000
Balance at Dec. 31, 2022	526,848	$ 21,187	627,565	386,617	$ (425,768)	(70,519)	(12,234)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(62,255)			(62,255)
Dividend	(5,714)			(5,714)
Shares withheld on employee taxes on vested equity awards (in shares)					21,000
Shares withheld on employee taxes on vested equity awards	(254)				$ (254)
Amortization of deferred compensation	570						570
Equity awards granted, net (in shares)		0			(40,000)
Equity awards granted, net		$ 0	(617)		$ 617
ESOP allocation of common stock	1,207		1,207
Stock-based compensation	5,296		5,296
Other comprehensive income, net of tax	2,613					2,613
Ending balance (in shares) at Mar. 31, 2023		84,746,000
Ending balance (in shares) at Mar. 31, 2023					27,541,000
Balance at Mar. 31, 2023	468,311	$ 21,187	633,451	318,648	$ (425,405)	(67,906)	(11,664)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	49,205			49,205
Dividend	(121,461)			(121,461)
Amortization of deferred compensation	6,630						6,630
Common stock acquired (in shares)					2,542,000
Common stock acquired	(86,009)				$ (86,009)
ESOP allocation of common stock	13,609		13,609
Stock-based compensation	5,106		5,106
Other comprehensive income, net of tax	315					315
Ending balance (in shares) at Jun. 30, 2023		84,746,000
Ending balance (in shares) at Jun. 30, 2023					30,083,000
Balance at Jun. 30, 2023	$ 335,706	$ 21,187	$ 652,166	$ 246,392	$ (511,414)	$ (67,591)	$ (5,034)