CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock Tri Valley Bank	Common Stock United American Bank	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income / (Loss)	Tri Valley Bank	United American Bank	Total
Balance at Dec. 31, 2016			$ 215,237	$ 52,527	$ (7,914)			$ 259,850
Balance (in shares) at Dec. 31, 2016			37,941,007
Increase (Decrease) in Shareholders' Equity
Net income				13,987				13,987
Other comprehensive loss					1,447			1,447
Issuance of restricted stock awards, net (in shares)			81,886
Amortization of restricted stock awards, net of forfeitures and taxes			$ 450					450
Cash dividend declared				(7,604)				(7,604)
Stock option expense, net of forfeitures and taxes			441					441
Stock options exercised			$ 660					660
Stock options exercised (in shares)			97,370
Balance at Jun. 30, 2017			$ 216,788	58,910	(6,467)			269,231
Balance (in shares) at Jun. 30, 2017			38,120,263
Balance at Dec. 31, 2017			$ 218,355	62,136	(9,252)			271,239
Balance (in shares) at Dec. 31, 2017			38,200,883
Increase (Decrease) in Shareholders' Equity
Net income				9,724				9,724
Other comprehensive loss					(6,614)			(6,614)
Issuance of common shares to acquire Business	$ 30,725	$ 47,280				$ 30,725	$ 47,280
Issuance of common shares to acquire Business (in shares)	1,889,613	2,826,032
Issuance of restricted stock awards, net (in shares)			97,818
Amortization of restricted stock awards, net of forfeitures and taxes			$ 511					511
Cash dividend declared				(8,949)				(8,949)
Stock option expense, net of forfeitures and taxes			351					351
Stock options exercised			$ 2,002					2,002
Stock options exercised (in shares)			207,838
Balance at Jun. 30, 2018			$ 299,224	$ 62,911	$ (15,866)			$ 346,269
Balance (in shares) at Jun. 30, 2018			43,222,184