Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 37,501	$ 35,278
Adjustments to reconcile net income to net cash provided by operating activities:
FHLB stock dividends	(2,425)	(2,233)
Provision for credit losses	675	233
Originations of loans receivable held-for-sale ("LHFS")	(1,325)	(2,769)
Proceeds from sales of LHFS	1,881	2,868
Amortization and accretion of premiums and discounts on securities	2,866	4,515
Depreciation and amortization of premises and equipment	3,122	2,581
Amortization of deferred amounts related to FHLB advances, net	3,631	4,143
Common stock committed to be released for allocation - ESOP	1,014	3,276
Stock-based compensation	1,105	1,586
Changes in:
Prepaid federal insurance premium		1,977
Accrued interest receivable	404	1,645
Other assets, net	692	(915)
Income taxes payable/receivable	4,707	3,801
Accounts payable and accrued expenses	(10,151)	(12,242)
Net cash provided by operating activities	43,697	43,744
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of AFS securities	(120,817)	(379,187)
Purchase of HTM securities	(159,707)	(420,501)
Proceeds from calls, maturities and principal reductions of AFS securities	291,348	529,899
Proceeds from calls, maturities and principal reductions of HTM securities	154,790	350,510
Proceeds from the redemption of capital stock of FHLB	7,845	4,524
Purchases of capital stock of FHLB	(2,719)
Net increase in loans receivable	(97,805)	(111,672)
Purchases of premises and equipment	(4,003)	(6,233)
Proceeds from sales of OREO	2,814	5,858
Net cash provided by (used in) investing activities	71,746	(26,802)
CASH FLOWS FROM FINANCING ACTIVITIES:
Dividends paid	(82,792)	(125,325)
Deposits, net of withdrawals	82,316	142,930
Proceeds from borrowings	420,180	403,130
Repayments on borrowings	(470,180)	(453,130)
Change in advance payments by borrowers for taxes and insurance	(7,223)	(5,683)
Repurchase of common stock	(57,206)	(71,995)
Stock options exercised	411
Net cash used in financing activities	(114,494)	(110,073)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	949	(93,131)
CASH AND CASH EQUIVALENTS:
Beginning of Period	113,886	141,705
End of Period	114,835	48,574
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Income tax payments	13,700	14,391
Interest payments	50,880	58,747
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
FHLB advances that will settle in a subsequent period		$ 100,000