Securities (Tables)

3 Months Ended

Dec. 31, 2019

Marketable Securities [Abstract]

Amortized Cost, Estimated Fair Value, And Gross Unrealized Gains And Losses Of AFS Securities

The following tables reflect the amortized cost, estimated fair value, and gross unrealized gains and losses of AFS securities at the dates presented. The majority of the MBS and investment securities portfolios are composed of securities issued by United States government-sponsored enterprises ("GSEs").

	December 31, 2019
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
	(Dollars in thousands)
MBS	$	924,732	$	14,983	$	2,398	$	937,317
GSE debentures	274,994		257		96		275,155
Municipal bonds	17,050		65		—		17,115
	$	1,216,776	$	15,305	$	2,494	$	1,229,587

	September 30, 2019
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
	(Dollars in thousands)
MBS	$	923,256	$	15,571	$	2,340	$	936,487
GSE debentures	249,828		304		178		249,954
Municipal bonds	18,371		52		1		18,422
	$	1,191,455	$	15,927	$	2,519	$	1,204,863

Schedule Of Estimated Fair Value And Gross Unrealized Losses Of Securities In Continuous Unrealized Loss Position

The following tables summarize the estimated fair value and gross unrealized losses of those AFS securities on which an unrealized loss at the dates presented was reported and the continuous unrealized loss position for less than 12 months and equal to or greater than 12 months as of the dates presented.

	December 31, 2019
	Less Than 12 Months				Equal to or Greater Than 12 Months
	Estimated		Unrealized		Estimated		Unrealized
	Fair Value		Losses		Fair Value		Losses
	(Dollars in thousands)
MBS	$	71,249	$	387	$	174,037	$	2,011
GSE debentures	24,946		54		74,952		42
Municipal bonds	—		—		—		—
	$	96,195	$	441	$	248,989	$	2,053

	September 30, 2019
	Less Than 12 Months				Equal to or Greater Than 12 Months
	Estimated		Unrealized		Estimated		Unrealized
	Fair Value		Losses		Fair Value		Losses
	(Dollars in thousands)
MBS	$	111,368	$	126	$	199,442	$	2,214
GSE debentures	—		—		74,812		178
Municipal bonds	1,755		1		—		—
	$	113,123	$	127	$	274,254	$	2,392

Schedule Of Contractual Maturities

The amortized cost and estimated fair value of AFS debt securities as of December 31, 2019, by contractual maturity, are shown below.  Actual principal repayments may differ from contractual maturities due to prepayment or early call privileges by the issuer. In the case of MBS, borrowers on the underlying loans generally have the right to prepay their loans without prepayment penalty. For this reason, MBS are not included in the maturity categories.

	Amortized		Estimated
	Cost		Fair Value
	(Dollars in thousands)
One year or less	$	81,453	$	81,417
One year through five years	185,591		185,853
Five years through ten years	25,000		25,000
	292,044		292,270
MBS	924,732		937,317
	$	1,216,776	$	1,229,587

Schedule Of Taxable And Non-taxable Components Of Interest Income

The following table presents the taxable and non-taxable components of interest income on investment securities for the periods presented.

	For the Three Months Ended
	December 31,
	2019		2018
	(Dollars in thousands)
Taxable	$	1,437	$	1,348
Non-taxable	70		93
	$	1,507	$	1,441

Schedule Of Carrying Value Of Securities Pledged As Collateral

The following table summarizes the carrying value of securities pledged as collateral for the obligations indicated below as of the dates presented.

	December 31, 2019		September 30, 2019
	(Dollars in thousands)
Public unit deposits	$	307,875	$	381,143
Repurchase agreements	108,000		108,271
Federal Reserve Bank of Kansas City ("FRB of Kansas City")	6,109		6,636
	$	421,984	$	496,050