Parent Company - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net income	$ 234,983	$ 265,685	$ 265,735
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	(13,656)	22,138	14,120
Stock-based compensation	9,609	10,298	13,106
Change in assets and liabilities:
Net decrease (increase) in other assets	(40,156)	18,469	(8,211)
Net increase in other liabilities	559	53,523	110,613
Net cash provided by operating activities	255,026	430,614	417,125
Cash flows from financing activities
Dividends paid	(132,646)	(132,588)	(134,133)
Stock tendered for payment of withholding taxes	(3,215)	(3,555)	(3,108)
Proceeds from employee stock purchase plan	308	379	547
Common stock repurchased		(9,478)	(75,000)
Net cash provided by financing activities	(66,925)	(197,359)	2,176,719
Net increase (decrease) in cash and cash equivalents	1,213,273	(731,845)	217,525
Cash and cash equivalents at beginning of year	526,624	1,258,469	1,040,944
Cash and cash equivalents at end of year	1,739,897	526,624	1,258,469
First Hawaiian, Inc.
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed income of FHB	(102,670)	(117,801)	(58,135)
Deferred income taxes	(96)	22	36
Stock-based compensation	584	554	492
Change in assets and liabilities:
Net decrease (increase) in other assets	164	(4)	242
Net increase in other liabilities	39	18	50
Net cash provided by operating activities	133,004	148,474	208,420
Cash flows from financing activities
Dividends paid	(132,646)	(132,588)	(134,133)
Stock tendered for payment of withholding taxes	(3,215)	(3,555)	(3,108)
Proceeds from employee stock purchase plan	308	379	547
Common stock repurchased		(9,478)	(75,000)
Net cash provided by financing activities	(135,553)	(145,242)	(211,694)
Net increase (decrease) in cash and cash equivalents	(2,549)	3,232	(3,274)
Cash and cash equivalents at beginning of year	18,024	14,792	18,066
Cash and cash equivalents at end of year	$ 15,475	$ 18,024	$ 14,792