Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ (16,305)				$ (16,305)
Other comprehensive income (loss), before reclassifications - AFS Securities	$ (31,117)			$ 5,703			(107,544)	$ (14,091)
Other comprehensive income (loss), before reclassifications - Cash Flow Hedges	3,798			(2,212)			17,127	5,743
Amount reclassified from AOCI - AFS Securities	0			0			0	0
Amount reclassified from AOCI - Cash Flow Hedges	1,301			2,124			4,797	11,515
Amount reclassified from AOCI, deferred income taxes	(420)			(686)			(1,548)	(3,717)
Other comprehensive income (loss) - AFS Securities	(31,117)			5,703			(107,544)	(14,091)
Other comprehensive income (loss) - Cash Flow Hedges	5,099			(88)			21,924	17,258
Other comprehensive income (loss)	(26,018)	$ (52,581)	(7,021)	5,615	$ (7,582)	$ 5,134
Ending balance	(101,925)						(101,925)
Unrealized Gains (Losses) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(71,776)		4,651	3,934		23,728	4,651	23,728
Ending balance	(102,893)	(71,776)		9,637	3,934		(102,893)	9,637
Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(4,131)		(20,956)	(22,887)		(40,233)	(20,956)	(40,233)
Ending balance	968	(4,131)		(22,975)	(22,887)		968	(22,975)
AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(75,907)		(16,305)	(18,953)		(16,505)	(16,305)	(16,505)
Other comprehensive income (loss), before reclassifications	(27,319)			3,491			(90,417)	(8,348)
Amount reclassified from AOCI	1,301			2,124			4,797	11,515
Other comprehensive income (loss)	(26,018)	(52,581)	$ (7,021)	5,615	(7,582)	$ 5,134	(85,620)	3,167
Ending balance	$ (101,925)	$ (75,907)		$ (13,338)	$ (18,953)		$ (101,925)	$ (13,338)