Significant Accounting Policies (Details) $ in Thousands				12 Months Ended
	Oct. 10, 2018 USD ($) Branch	Oct. 09, 2018 USD ($)	Nov. 18, 2016 USD ($) Branch	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Acquisitions [Abstract]
Gain on remeasurement of previously held equity investment				$ 997	$ 0	$ 0
Assets				$ 3,434,243	$ 3,075,452
Bank of Rio Vista [Member]
Acquisitions [Abstract]
Percentage of equity interest in acquiree prior to acquisition of remaining interest		39.65%
Gain on remeasurement of previously held equity investment		$ 997
Assets	$ 217,500
Number of branches | Branch	3
Delta National Bancorp [Member]
Acquisitions [Abstract]
Assets			$ 112,000
Number of branches | Branch			4