Parent Company - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and Due from Banks	$ 246,716	$ 303,373
Other assets	643,240	603,463
Total assets	24,992,410	22,662,831	$ 20,166,734
Liabilities and Stockholders' Equity
Retirement benefits payable	134,491	143,373
Other liabilities	384,861	347,621
Total liabilities	22,335,498	19,918,727
Stockholders' equity
Stockholders' equity	2,656,912	2,744,104	$ 2,640,258	$ 2,524,839
Total liabilities and stockholders' equity	24,992,410	22,662,831
First Hawaiian, Inc.
Assets
Cash and Due from Banks	14,792	18,066
Investment in FHB	2,642,929	2,726,497
Other assets	26,869	26,138
Total assets	2,684,590	2,770,701
Liabilities and Stockholders' Equity
Retirement benefits payable	582	580
Other liabilities	27,096	26,017
Total liabilities	27,678	26,597
Stockholders' equity
Total liabilities and stockholders' equity	$ 2,684,590	$ 2,770,701