Acquisition of First Priority Financial Corp. (Pro Forma Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Net interest income after loan loss provision	$ 17,305	$ 11,414	$ 34,486	$ 22,167
Noninterest income	2,874	1,913	4,923	3,560
Noninterest expense	$ 14,796	10,096	$ 29,099	21,279
First Priority Financial Corp. [Member]
Business Acquisition [Line Items]
Net interest income after loan loss provision		16,235		31,655
Noninterest income		2,192		4,003
Noninterest expense		12,439		26,969
Net income		$ 5,308		$ 8,251
Net income per common share		$ 0.63		$ 0.99