CONDENSED CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - 9 months ended Jun. 30, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	COMMON STOCK [Member]	CAPITAL INEXCESS OF PAR VALUE [Member]	RETAINED EARNINGS [Member]	TREASURY SHARES [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) [Member]	DEFERRED COMPENSATION [Member]
Balance at Sep. 30, 2017	$ 398,808	$ 20,166	$ 487,077	$ 480,347	$ (489,225)	$ (60,481)	$ (39,076)
Balance (in Shares) at Sep. 30, 2017		80,663			33,557
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	127,096			127,096
Dividend	(52,521)			(52,521)
Shares withheld on employee taxes on vested equity awards			0
Shares withheld on employee taxes on vested equity awards					199
Shares withheld on employee taxes on vested equity awards	(4,478)				$ (4,478)
Amortization of deferred compensation	6,088						6,088
Common stock acquired (in shares)					2,089
Common stock acquired	(41,110)				$ (41,110)
Equity awards granted, net (in shares)		797
Equity awards granted, net	0	$ 199	(199)
ESOP allocation of common stock	3,906		3,906
Stock-based compensation	7,372		7,372
Other comprehensive income, net of tax	19,954					19,954
Balance at Jun. 30, 2018	$ 466,087	$ 20,365	$ 499,128	$ 554,922	$ (534,813)	$ (40,527)	$ (32,988)
Balance (in Shares) at Jun. 30, 2018		81,460			35,845