Note 4 - Loans and Allowance for Loan Losses - Troubled Debt Restructurings, Excluding Loans Acquired, Segregated by Class of Loans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Financing Receivable, Modifications, Number of Contracts	70	18
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	2	1
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	51	12
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Financing Receivable, Modifications, Number of Contracts	23	11
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	17	5
Loans, Excluding Acquired Loans [Member]
Financing Receivable, Modifications, Number of Contracts	79	25
Troubled debt, balance	$ 14,174	$ 5,561
Loans, Excluding Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled debt, balance	$ 3	$ 13
Loans, Excluding Acquired Loans [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled debt, balance	$ 3	$ 13
Loans, Excluding Acquired Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	58	19
Troubled debt, balance	$ 12,091	$ 5,216
Loans, Excluding Acquired Loans [Member] | Commercial Real Estate Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Modifications, Number of Contracts	25	5
Troubled debt, balance	$ 9,828	$ 3,491
Loans, Excluding Acquired Loans [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled debt, balance	$ 18	$ 253
Loans, Excluding Acquired Loans [Member] | Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Financing Receivable, Modifications, Number of Contracts	32	13
Troubled debt, balance	$ 2,245	$ 1,472
Loans, Excluding Acquired Loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	20	5
Troubled debt, balance	$ 2,080	$ 332
Loans, Excluding Acquired Loans [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Financing Receivable, Modifications, Number of Contracts	20	5
Troubled debt, balance	$ 2,080	$ 332
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member]
Financing Receivable, Modifications, Number of Contracts	41	6
Troubled debt, balance	$ 10,998	$ 3,031
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts
Troubled debt, balance
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Modifications, Number of Contracts
Troubled debt, balance
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	26	6
Troubled debt, balance	$ 9,215	$ 3,031
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Modifications, Number of Contracts	23	4
Troubled debt, balance	$ 9,048	$ 2,894
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Modifications, Number of Contracts
Troubled debt, balance
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Financing Receivable, Modifications, Number of Contracts	3	2
Troubled debt, balance	$ 167	$ 137
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	15
Troubled debt, balance	$ 1,783
Loans, Excluding Acquired Loans [Member] | Performing Financial Instruments [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Financing Receivable, Modifications, Number of Contracts	15
Troubled debt, balance	$ 1,783
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications, Number of Contracts	38	19
Troubled debt, balance	$ 3,176	$ 2,530
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled debt, balance	$ 3	$ 13
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled debt, balance	$ 3	$ 13
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	32	13
Troubled debt, balance	$ 2,876	$ 2,185
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Modifications, Number of Contracts	2	1
Troubled debt, balance	$ 780	$ 597
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Modifications, Number of Contracts	1	1
Troubled debt, balance	$ 18	$ 253
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Financing Receivable, Modifications, Number of Contracts	29	11
Troubled debt, balance	$ 2,078	$ 1,335
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	5	5
Troubled debt, balance	$ 297	$ 332
Loans, Excluding Acquired Loans [Member] | Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Financing Receivable, Modifications, Number of Contracts	5	5
Troubled debt, balance	$ 297	$ 332