Bank of Hawaii Corporation Financial Statements (Condensed Statements of Cash Flows) (Details 3) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Share-Based Compensation	$ 8,337	$ 8,146	$ 7,369
Net Losses (Gains) on Investment Securities	3,986	3,938	(10,430)
Net Change in Other Assets and Other Liabilities	(20,039)	27,815	(60,622)
Investing Activities
Purchase of Investment Securities Held-to-Maturity Securities	(1,380,430)	(419,640)	(995,076)
Financing Activities
Proceeds from Issuance of Common Stock	7,872	7,873	13,101
Repurchase of Common Stock	(137,649)	(91,988)	(47,076)
Cash Dividends Paid	(105,478)	(98,496)	(87,066)
Cash and Cash Equivalents at Beginning of Period	525,969
Cash and Cash Equivalents at End of Period	558,658	525,969
Parent Company [Member]
Operating Activities
Net Income	225,913	219,602	184,672
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Share-Based Compensation	760	630	573
Net Losses (Gains) on Investment Securities	850	819	(12,027)
Equity in Undistributed Income of Subsidiaries	(7,134)	(35,429)	(48,119)
Net Change in Other Assets and Other Liabilities	(135)	870	(6,477)
Net Cash Provided by Operating Activities	220,254	186,492	118,622
Investing Activities
Payments for (Proceeds from) Businesses and Interest in Affiliates	0	0	613
Payments for (Proceeds from) Long-term Investments	0	0	12,467
Proceeds from Sales of Investment Securities	(4,259)	819	(12,027)
Purchase of Investment Securities Held-to-Maturity Securities	(4,933)	0	0
Net Cash Provided by (Used in) Investing Activities	(674)	(819)	173
Financing Activities
Proceeds from Issuance of Common Stock	7,872	7,873	13,101
Repurchase of Common Stock	(137,649)	(91,988)	(47,076)
Cash Dividends Paid	(105,478)	(98,496)	(87,066)
Net Cash Provided by (Used in) Financing Activities	(235,255)	(182,611)	(121,041)
Net Change in Cash and Cash Equivalents	(15,675)	3,062	(2,246)
Cash and Cash Equivalents at Beginning of Period	52,731	49,669	51,915
Cash and Cash Equivalents at End of Period	$ 37,056	$ 52,731	$ 49,669

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