Parent Company Financial Information, Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Statements of Income [Abstract]
Interest Income	$ 95,070	$ 86,750	$ 78,708
Tax Benefit	(16,097)	(16,924)	(15,094)
Net Income	29,723	27,392	25,402
Parent Company [Member]
Condensed Statements of Income [Abstract]
Equity in Undistributed Earnings in Farmers & Merchants Bank of Central California	17,043	17,352	18,211
Dividends from Subsidiary	14,275	10,875	8,000
Interest Income	11	10	10
Other Expenses, Net	(2,485)	(1,451)	(1,406)
Tax Benefit	879	606	587
Net Income	$ 29,723	$ 27,392	$ 25,402