Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (16,305)
Other comprehensive income (loss), before reclassifications - AFS Securities	(10,982)	$ 1,140
Other comprehensive income (loss), before reclassifications - Cash Flow Hedges	2,178	1,024
Amount reclassified from AOCI - AFS Securities	0	0
Amount reclassified from AOCI - Cash Flow Hedges	1,783	2,970
Amount reclassified from AOCI, deferred income taxes	(575)	(959)
Other comprehensive income (loss) - AFS Securities	(10,982)	1,140
Other comprehensive income (loss) - Cash Flow Hedges	3,961	3,994
Other comprehensive income (loss)	(7,021)	5,134
Ending balance	(23,326)
Unrealized Gains (Losses) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	4,651	23,728
Ending balance	(6,331)	24,868
Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(20,956)	(40,233)
Ending balance	(16,995)	(36,239)
AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(16,305)	(16,505)
Other comprehensive income (loss), before reclassifications	(8,804)	2,164
Amount reclassified from AOCI	1,783	2,970
Other comprehensive income (loss)	(7,021)	5,134
Ending balance	$ (23,326)	$ (11,371)