Parent Company Only - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets
Prepaid expenses and other assets	$ 8,211	$ 6,676
Total assets	2,236,672	2,169,592
Liabilities and Equity
Equity	251,086	256,550	$ 256,322
Total liabilities and stockholders' equity	2,236,672	2,169,592
Territorial Bancorp Inc.
Assets
Cash	18,453	28,515
Investment in Territorial Savings Bank	232,751	227,663
Prepaid expenses and other assets	272	105
Total assets	251,476	256,691
Liabilities and Equity
Other liabilities	390	141
Equity	251,086	256,550
Total liabilities and stockholders' equity	$ 251,476	256,691
Territorial Bancorp Inc. | Territorial Savings Bank
Assets
Receivable from Territorial Savings Bank		$ 408