Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2017
Operating Activities
Net Income	$ 115,718	$ 108,758
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Provision for Credit Losses	7,000	7,625
Depreciation and Amortization	8,232	6,788
Amortization of Deferred Loan and Lease Fees	(487)	(292)
Amortization and Accretion of Premiums/Discounts on Investment Securities, Net	9,951	17,632
Amortization of Operating Lease Right-of-Use Assets	6,359	0
Share-Based Compensation	4,438	4,055
Benefit Plan Contributions	(887)	(798)
Deferred Income Taxes	(2,711)	(2,496)
Gain (Loss) on Sale of Premises and Equipment	(558)	0
Net Gains on Sales of Loans and Leases	(2,166)	(1,070)
Net Losses (Gains) on Sales of Investment Securities	1,611	2,368
Proceeds from Sales of Loans Held for Sale	162,426	152,004
Originations of Loans Held for Sale	(173,117)	(148,513)
Net Tax Benefit from Share-Based Compensation	637	949
Net Change in Other Assets and Other Liabilities	(36,486)	(18,529)
Net Cash Provided by Operating Activities	99,960	128,481
Investment Securities Available-for-Sale:
Proceeds from Sales, Prepayments and Maturities	1,423,672	209,572
Purchases	(1,029,942)	(99,254)
Investment Securities Held-to-Maturity:
Proceeds from Prepayments and Maturities	367,211	425,043
Purchases	(864,955)	(99,415)
Net Change in Loans and Leases	(316,228)	(264,304)
Purchases of Premises and Equipment	(26,146)	(18,652)
Proceeds from Sale of Premises and Equipment	639	0
Net Cash Provided by (Used in) Investing Activities	(445,749)	152,990
Financing Activities
Net Change in Deposits	461,579	59,390
Net Change in Short-Term Borrowings	(196)	(770)
Repayments of Long-Term Debt	(25,038)	(25,000)
Proceeds from Issuance of Common Stock	4,214	4,498
Repurchase of Common Stock	(78,175)	(42,229)
Cash Dividends Paid	(52,201)	(47,451)
Net Cash Provided by (Used in) Financing Activities	310,183	(51,562)
Net Change in Cash and Cash Equivalents	(35,606)	229,909
Cash and Cash Equivalents at End of Period	490,363	677,760
Cash and Cash Equivalents at Beginning of Period	525,969	447,851
Supplemental Information
Cash Paid for Interest	44,077	27,830
Cash Paid for Income Taxes	29,868	24,487
Non-Cash Investing and Financing Activities:
Initial Recognition of Operating Lease Right-of-Use Assets	103,336
Initial Recognition of Operating Lease Liabilities	110,483
Transfer from Investments	1,014,859		$ 0
Transfer from Loans to Foreclosed Real Estate	$ 1,869	$ 2,307