Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Percentage of selling costs		10.00%
Investment Securities Available-for-Sale		$ 495,396	$ 481,596
Transfer into Level 3		0
Transfer out of Level 3		0
Gains (losses) for assets categorized as Level 3 assets		0
Government Agency & Government-Sponsored Entities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		3,039	3,128
US Treasury Notes [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		164,514	144,164
US Govt SBA [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		15,447	29,380
Mortgage Backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale	[1]	307,045	301,914
Other [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		5,351	3,010
Significant Unobservable Inputs (Level 3) [Member] | SBA Loans [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		2,500
Significant Unobservable Inputs (Level 3) [Member] | California Reclamation Districts [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		1,600
Significant Unobservable Inputs (Level 3) [Member] | Pacific Coast Bankers' Bank and The Independent Bankers' Bank Stock [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		745
Recurring [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		495,396	481,596
Recurring [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		3,039	3,128
Recurring [Member] | US Treasury Notes [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		164,514	144,164
Recurring [Member] | US Govt SBA [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		15,447	29,380
Recurring [Member] | Mortgage Backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		307,045	301,914
Recurring [Member] | Other [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		5,351	3,010
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		164,716	144,364
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | US Treasury Notes [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		164,514	144,164
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | US Govt SBA [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage Backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		202	200
Recurring [Member] | Other Observable Inputs (Level 2) [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		325,841	334,732
Recurring [Member] | Other Observable Inputs (Level 2) [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		3,039	3,128
Recurring [Member] | Other Observable Inputs (Level 2) [Member] | US Treasury Notes [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Other Observable Inputs (Level 2) [Member] | US Govt SBA [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		15,447	29,380
Recurring [Member] | Other Observable Inputs (Level 2) [Member] | Mortgage Backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		307,045	301,914
Recurring [Member] | Other Observable Inputs (Level 2) [Member] | Other [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		310	310
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		4,839	2,500
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Government Agency & Government-Sponsored Entities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | US Treasury Notes [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | US Govt SBA [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage Backed Securities [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		0	0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Assets Measured at Fair Value on Recurring Basis by Fair Value Hierarchy [Abstract]
Investment Securities Available-for-Sale		$ 4,839	$ 2,500

[1] All Mortgage Backed Securities were issued by an agency or government sponsored entity of the U.S. government.