CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital In Excess Of Par Value [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Deferred Compensation [Member]
Balance (in Shares) at Sep. 30, 2015		79,080,000			30,737,000
Balance at Sep. 30, 2015	$ 430,525	$ 19,770	$ 518,485	$ 454,548	$ (436,559)	$ (91,188)	$ (34,531)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	30,010			30,010
Payments of Ordinary Dividends, Common Stock	8,798			(8,798)
Dividends	(8,798)
Amortization of deferred compensation	2,853						2,853
Common stock issued (in Shares)		41,000
Common stock issued		$ 10	(10)
Common stock acquired (in Shares)					4,060,000
Common stock acquired	(65,307)				$ (65,307)
Equity awards granted, net (in Shares)		845,000
Equity awards granted, net	264	$ 212	52
ESOP allocation of common stock	1,317		1,317
Stock-based compensation	10,136		10,136
Other comprehensive income, net of tax	9,947					9,947
Balance (in Shares) at Sep. 30, 2016		79,966,000			34,797,000
Balance at Sep. 30, 2016	410,947	$ 19,992	529,980	475,760	$ (501,866)	(81,241)	(31,678)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14,912			14,912
Payments of Ordinary Dividends, Common Stock	10,325
Dividends	(10,325)			(10,325)
Tax effect from exercise/vesting of equity awards, net	(13,738)		(97)		$ (13,641)
Tax effect from exercise/vesting of equity awards, net (in shares)					586,000
Amortization of deferred compensation	3,510						3,510
Common stock issued (in Shares)		3,000
Common stock issued	22		22
Common stock acquired (in Shares)					129,000
Common stock acquired	(2,201)				$ (2,201)
Equity awards granted, net (in Shares)		694,000
Equity awards granted, net		$ 174	(174)
Premium on settlement of convertible debt	(73,855)		(73,855)
Issuance of treasury stock in settlement of convertible debt	48,858		20,375		$ 28,483
Issuance of treasury stock in settlement of convertible debt (in shares)					(1,955,000)
ESOP purchase of common stock	(10,908)						(10,908)
ESOP allocation of common stock	2,736		2,736
Stock-based compensation	8,090		8,090
Other comprehensive income, net of tax	20,760					20,760
Balance (in Shares) at Sep. 30, 2017		80,663,000			33,557,000
Balance at Sep. 30, 2017	398,808	$ 20,166	487,077	480,347	$ (489,225)	(60,481)	(39,076)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	125,678			125,678
Payments of Ordinary Dividends, Common Stock	49,797
Dividends	$ (55,502)			(55,502)
Tax effect from exercise/vesting of equity awards, net (in shares)	2,088,739
Shares paid for tax withholding for share based compensation (in Shares)	199,978				200,000
Shares withheld on employee taxes on vested equity awards	$ (4,495)				$ (4,495)
Amortization of deferred compensation	8,110						8,110
Common stock acquired (in Shares)					2,089,000
Common stock acquired	(41,110)				$ (41,110)
Equity awards granted, net (in Shares)		857,000
Equity awards granted, net		$ 214	(214)
ESOP allocation of common stock	4,756		4,756
Stock-based compensation	10,078		10,078
Stock-based consideration	1,699		1,699
Other comprehensive income, net of tax	26,369					26,369
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)