Note 3 - Acquisition (Detail) - Bargain Purchase Gain on Acquisition (USD $) In Thousands	0 Months Ended
	Aug. 20, 2010
Sonoma Valley Bank tangible shareholder's equity	$ 13,923
Gain on acquisition	178
Cash Payment From FDIC [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	21,270
Loans And Leases Net [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	(34,562)
Other Real Estate Owned [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	(1,491)
Other Assets [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	(811)
Core Deposits [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	5,270
Deposits [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	(1,233)
Federal Home Loan Bank Advances [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	(1,872)
Other Liabilities [Member]
Adjustment to reflect assets acquired and liabilities assumed at fair value	$ (316)