Subsequent Events	12 Months Ended
Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	22. Subsequent Events On January 17, 2023, the Company terminated both of its interest rate swap derivative instruments at a gain of $849,000. Also, $536,000 of cash posted to the counterparty as collateral on these interest rate swaps contracts was returned to the Company. On January 19, 2023, the conversion of First Seacoast Bancorp, MHC from mutual to stock form and the related stock offering by First Seacoast Bancorp, Inc., the new holding company for First Seacoast Bank, was completed. First Seacoast Bancorp, Inc.’s common stock began trading on the Nasdaq Capital Market under the trading symbol “FSEA” on January 20, 2023. As a result of the subscription offering, the community offering and the syndicated community offering, First Seacoast Bancorp, Inc. sold a total of 2,805,000 shares of its common stock at a price of $10.00 per share, which includes 224,400 shares sold to First Seacoast Bank’s Employee Stock Ownership Plan. As part of the conversion transaction, each outstanding share of First Seacoast Bancorp (a federal corporation) common stock owned by the public stockholders of First Seacoast Bancorp (a federal corporation) (stockholders other than First Seacoast Bancorp, MHC) as of the closing date was converted into shares of First Seacoast Bancorp, Inc. common stock based on an exchange ratio of 0.8358 shares of First Seacoast Bancorp, Inc. common stock for each share of First Seacoast Bancorp (a federal corporation) common stock. Cash was issued in lieu of a fractional share of First Seacoast Bancorp, Inc. common stock based on the offering price of $10.00 per share. Upon the completion of the conversion transaction, First Seacoast Bancorp, Inc. has approximately 5,077,492 shares of common stock outstanding.

Subsequent Events

12 Months Ended

Dec. 31, 2022

22.

Subsequent Events

On January 17, 2023, the Company terminated both of its interest rate swap derivative instruments at a gain of $849,000. Also, $536,000 of cash posted to the counterparty as collateral on these interest rate swaps contracts was returned to the Company.

On January 19, 2023, the conversion of First Seacoast Bancorp, MHC from mutual to stock form and the related stock offering by First Seacoast Bancorp, Inc., the new holding company for First Seacoast Bank, was completed. First Seacoast Bancorp, Inc.’s common stock began trading on the Nasdaq Capital Market under the trading symbol “FSEA” on January 20, 2023. As a result of the subscription offering, the community offering and the syndicated community offering, First Seacoast Bancorp, Inc. sold a total of 2,805,000 shares of its common stock at a price of $10.00 per share, which includes 224,400 shares sold to First Seacoast Bank’s Employee Stock Ownership Plan. As part of the conversion transaction, each outstanding share of First Seacoast Bancorp (a federal corporation) common stock owned by the public stockholders of First Seacoast Bancorp (a federal corporation) (stockholders other than First Seacoast Bancorp, MHC) as of the closing date was converted into shares of First Seacoast Bancorp, Inc. common stock based on an exchange ratio of 0.8358 shares of First Seacoast Bancorp, Inc. common stock for each share of First Seacoast Bancorp (a federal corporation) common stock. Cash was issued in lieu of a fractional share of First Seacoast Bancorp, Inc. common stock based on the offering price of $10.00 per share. Upon the completion of the conversion transaction, First Seacoast Bancorp, Inc. has approximately 5,077,492 shares of common stock outstanding.