Parent Company - Condensed Statements of Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash and due from banks	$ 185,015	$ 297,502
Other assets	845,662	796,954
Total assets	24,926,474	24,577,223	$ 24,992,410
Liabilities and Stockholders' Equity
Retirement benefits payable	103,285	102,577
Other liabilities	504,466	441,612
Total liabilities	22,440,408	22,308,218
Stockholders' equity
Total stockholders' equity	2,486,066	2,269,005	$ 2,656,912	$ 2,744,104
Total liabilities and stockholders' equity	24,926,474	24,577,223
First Hawaiian, Inc.
Assets
Cash and due from banks	15,475	18,024
Investment in FHB	2,471,679	2,251,841
Other assets	30,131	27,638
Total assets	2,517,285	2,297,503
Liabilities and Stockholders' Equity
Retirement benefits payable	688	560
Other liabilities	30,531	27,938
Total liabilities	31,219	28,498
Stockholders' equity
Total liabilities and stockholders' equity	$ 2,517,285	$ 2,297,503