Parent Company Financial Information, Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Balance Sheets [Abstract]
Investment Securities	$ 430,533	$ 430,405
Other Assets	88,057	96,367
Total Assets	2,615,345	2,360,551
Subordinated Debentures	10,310	10,310
Liabilities	2,363,510	2,127,373
Shareholders' Equity	251,835	233,178	$ 209,904	$ 205,033
Total Liabilities and Shareholders' Equity	2,615,345	2,360,551
Parent Company [Member]
Condensed Balance Sheets [Abstract]
Cash	308	363	$ 416	$ 212
Investment in Farmers & Merchants Bank of Central California	261,626	242,852
Investment Securities	409	410
Other Assets	60	201
Total Assets	262,403	243,826
Subordinated Debentures	10,310	10,310
Liabilities	258	338
Shareholders' Equity	251,835	233,178
Total Liabilities and Shareholders' Equity	$ 262,403	$ 243,826