Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Net Investment	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2015	$ 2,788,200				$ (51,259)	$ 2,736,941
Balance (in shares) at Dec. 31, 2015		139,459,620
Increase (Decrease) in Stockholders' Equity
Net income | Subsequent to reorganization on April 1, 2016				$ 108,095		108,095
Net income | Prior to reorganization on April 1, 2016	65,531					65,531
Net income						173,626
Distributions | Subsequent to reorganization on April 1, 2016			$ (69,938)			(69,938)
Distributions | Prior to reorganization on April 1, 2016	(363,624)					(363,624)
Contributions			61,992			61,992
Recapitalization of First Hawaiian, Inc.	$ (2,490,107)	$ 1,395	2,488,712
Cash dividends declared ($0.66 and $0.42 per share for nine months ended September 30, 2017 and 2016, respectively)				(57,891)		(57,891)
Equity-based awards			1,913			1,913
Other comprehensive income, net of tax					40,944	40,944
Balance at Sep. 30, 2016		$ 1,395	2,482,679	50,204	(10,315)	2,523,963
Balance (in shares) at Sep. 30, 2016		139,459,620
Balance at Jun. 30, 2016					(5,227)
Increase (Decrease) in Stockholders' Equity
Net income						53,235
Other comprehensive income, net of tax					(5,088)	(5,088)
Balance at Sep. 30, 2016		$ 1,395	2,482,679	50,204	(10,315)	2,523,963
Balance (in shares) at Sep. 30, 2016		139,459,620
Balance at Dec. 31, 2016		$ 1,395	2,484,251	78,850	(88,011)	$ 2,476,485
Balance (in shares) at Dec. 31, 2016		139,530,654				139,530,654
Increase (Decrease) in Stockholders' Equity
Net income				171,998		$ 171,998
Cash dividends declared ($0.66 and $0.42 per share for nine months ended September 30, 2017 and 2016, respectively)				(92,101)		(92,101)
Common stock issued under Employee Stock Purchase Plan			528			528
Common stock issued under Employee Stock Purchase Plan (in shares)		15,961
Equity-based awards		$ 1	4,494	(444)		4,051
Equity-based awards (in shares)		39,667
Other comprehensive income, net of tax					20,897	20,897
Balance at Sep. 30, 2017		$ 1,396	2,489,273	158,303	(67,114)	$ 2,581,858
Balance (in shares) at Sep. 30, 2017		139,586,282				139,586,282
Balance at Jun. 30, 2017					(67,651)
Increase (Decrease) in Stockholders' Equity
Net income						$ 58,363
Other comprehensive income, net of tax					537	537
Balance at Sep. 30, 2017		$ 1,396	$ 2,489,273	$ 158,303	$ (67,114)	$ 2,581,858
Balance (in shares) at Sep. 30, 2017		139,586,282				139,586,282