Intangible Assets (Schedule of Goodwill and Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill Balance	$ 9,324	$ 9,324	$ 9,324
Goodwill, Amortization	0	0	0
Goodwill Balance	9,324	9,324	9,324
Core Deposit and Other Intangibles Balance	746	1,520	2,589
Core Deposit and Other Intangibles, Amortization	(523)	(774)	(1,069)
Core Deposit and Other Intangibles Balance	$ 223	$ 746	$ 1,520

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets.

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+ Details

- Definition

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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+ Details

Capitol Federal Financial, Inc. 10-K