Federal Reserve Bank Stock (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Federal Reserve Bank Stock
Capital stock of the Federal Reserve Bank owned	$ 3,128	$ 3,114
Territorial Savings Bank
Federal Reserve Bank Stock
Requirement to hold shares of capital stock of the Federal Reserve Bank as a percentage of capital and surplus (as a percent)	6.00%
Capital stock of the Federal Reserve Bank owned	$ 3,100	$ 3,100

Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809

Name:	us-gaap_FederalReserveBankStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant