Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Net Investment	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Total
Balance at Dec. 31, 2014	$ 2,726,497				$ (51,457)		$ 2,675,040
Balance (in shares) at Dec. 31, 2014		139,459,620
Increase (Decrease) in Stockholders' Equity
Net income	213,780						213,780
Distributions	(164,228)						(164,228)
Contributions	12,151						12,151
Other comprehensive income, net of tax					198		198
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 | Prior to reorganization on April 1, 2016	65,531						65,531
Net income | Subsequent to reorganization on April 1, 2016				$ 164,647			164,647
Net income							230,178
Distributions | Prior to reorganization on April 1, 2016	(363,624)						(363,624)
Distributions | Subsequent to reorganization on April 1, 2016			$ (70,813)				(70,813)
Contributions | Subsequent to reorganization on April 1, 2016			61,992				61,992
Recapitalization of First Hawaiian, Inc.	$ (2,490,107)	$ 1,395	2,488,712
Cash dividends declared ($0.88 and $0.62 per share for years ended December 31, 2017 and 2016, respectively)				(85,797)			(85,797)
Equity-based awards			4,360				4,360
Equity-based awards (in shares)		71,034
Other comprehensive income, net of tax					(36,752)		(36,752)
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				183,682			$ 183,682
Distributions			(2,118)				(2,118)
Cash dividends declared ($0.88 and $0.62 per share for years ended December 31, 2017 and 2016, respectively)				(122,810)			(122,810)
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	5,982	(545)		$ (282)	5,156
Equity-based awards (in shares)		42,167
Other comprehensive income, net of tax					(8,372)		(8,372)
Balance at Dec. 31, 2017		$ 1,396	$ 2,488,643	$ 139,177	$ (96,383)	$ (282)	$ 2,532,551
Balance (in shares) at Dec. 31, 2017		139,588,782					139,588,782