Fair Value Measurements. - Additional Information (Detail) - USD ($)	5 Months Ended	12 Months Ended
Dec. 31, 2020	Dec. 31, 2021
Fair Value Measurements.
Fair value assets transfers	$ 0	$ 0
Decrease in the fair value		$ 388,000

Amount of increase (decrease) in fair value adjustment on other assets (liabilities) carried at fair value under the fair value option on the statement of cash flows of Federal Home Loan Banks (FHLBanks).

No definition available.

Name:	us-gaap_IncreaseDecreaseInFairValueAdjustmentsOnAssetsAndLiabilitiesCarriedAtFairValueUnderFairValueOption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration