Investment Securities (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($)	Jun. 30, 2023 USD ($) item security
Variable Interest Entity [Line Items]
Gross realized gains	$ 85		$ 85
Proceeds from sale of securities	$ 2,400	$ 0	$ 2,438	$ 0
Number of securities held for less than 12 months | security	2		2
Number of securities held for greater than 12 months	123		123		126
Number of securities temporarily impaired	123		123		126
Number of equity securities | security			1		1
Equity securities	$ 1,850		$ 1,850		$ 1,629
Unrealized gain (loss) on equity securities	$ 148	$ 54	$ 221	$ (219)
Financial Instrument, Owned, Pledged Status	Asset Pledged as Collateral without Right [Member]		Asset Pledged as Collateral without Right [Member]		Asset Pledged as Collateral without Right [Member]
Asset Pledged as Collateral
Variable Interest Entity [Line Items]
Pledged investment securities	$ 2,900		$ 2,900		$ 2,500
Asset Pledged as Collateral without Right [Member]
Variable Interest Entity [Line Items]
Financial Instrument, Owned, Pledging Purpose	wmpn:MunicipalDeposits		wmpn:MunicipalDeposits		wmpn:MunicipalDeposits