Acquisition of First Priority Financial Corp. (Pro Forma Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Net interest income after loan loss provision	$ 17,181	$ 10,753
Noninterest income	2,049	1,647
Noninterest expense	$ 14,303	11,183
First Priority Financial Corp. [Member]
Business Acquisition [Line Items]
Net interest income after loan loss provision		15,420
Noninterest income		1,811
Noninterest expense		14,530
Net income		$ 2,278
Net income per common share		$ 0.27