Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	May 04, 2018	Apr. 06, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Goodwill	$ 83,753,000			$ 45,664,000	$ 45,664,000
Goodwill acquired	38,089,000
BVF/CSNK
Goodwill
Goodwill acquired	13,044,000
Focus
Goodwill
Goodwill acquired	32,620,000
Tri Valley Bank
Goodwill
Goodwill			$ 13,819,000
Goodwill acquired	13,819,000
United American Bank
Goodwill
Goodwill		$ 24,270,000
Goodwill acquired	$ 24,270,000