Commitments and Contingent Liabilities - Contingencies (Details) - Overdraft fee litigation	12 Months Ended
	Dec. 31, 2016 item	Jan. 27, 2017 USD ($)
Contingencies
Loss contingency liability | $		$ 0
First Hawaiian Bank
Contingencies
Number of times a continuous negative balance overdraft fee charges on accounts remaining in negative balance for a seven-day period | item	1
Period for one-time continuous negative balance overdraft fee	7 days