Goodwill and Other Intangible Assets - Textuals (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment charges	$ 0	$ 0	$ 0
Premier Commercial | Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Puget Sound | Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Washington Banking | Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Valley Community Bancshares | Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	10 years
Northwest Commercial Bank | Core Deposits
Finite-Lived Intangible Assets [Line Items]
Useful life	5 years