Parent Company - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and due from banks	$ 297,502	$ 246,716
Other assets	796,954	643,240
Total assets	24,577,223	24,992,410	$ 22,662,831
Liabilities and Stockholders' Equity
Retirement benefits payable	102,577	134,491
Other liabilities	441,612	384,861
Total liabilities	22,308,218	22,335,498
Stockholders' equity
Stockholders' equity	2,269,005	2,656,912	$ 2,744,104	$ 2,640,258
Total liabilities and stockholders' equity	24,577,223	24,992,410
First Hawaiian, Inc.
Assets
Cash and due from banks	18,024	14,792
Investment in FHB	2,251,841	2,642,929
Other assets	27,638	26,869
Total assets	2,297,503	2,684,590
Liabilities and Stockholders' Equity
Retirement benefits payable	560	582
Other liabilities	27,938	27,096
Total liabilities	28,498	27,678
Stockholders' equity
Total liabilities and stockholders' equity	$ 2,297,503	$ 2,684,590