Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2007	Apr. 01, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill recorded	$ 15,017	$ 15,017
Accumulated amortization for intangible assets	6,900	6,800
Trade name intangible	950	950
Intangible asset amortization expense	100	135	$ 258
Alaska First
Finite-Lived Intangible Assets [Line Items]
Goodwill recorded				$ 1,800
CDI recorded				$ 1,300
Alaska Pacific Bank
Finite-Lived Intangible Assets [Line Items]
CDI recorded					$ 623
RML
Finite-Lived Intangible Assets [Line Items]
Goodwill recorded	7,500	7,500
Trade name intangible	950	950
Core Deposits | Alaska Pacific Bank
Finite-Lived Intangible Assets [Line Items]
Estimated useful life, years				10 years
Accumulated amortization for intangible assets	$ 365	$ 283	$ 190