Note 4 - Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans	$ 2,378,620,000	$ 2,277,727,000
Originated Loan [Member]
Past due loans	1,388,000	1,293,000
Current loans	1,883,160,000	1,615,294,000
Loans	1,884,548,000	1,616,587,000	$ 1,246,116,000
Loans past due 90 days or more still accruing interest	0	0
Acquired Loan [Member]
Past due loans	2,999,000	5,772,000
Current loans	491,073,000	655,368,000
Loans	494,072,000	661,140,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member]
Loans	2,065,347,000	1,946,696,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	713,903,000	696,303,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	34,828,000	45,120,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	450,464,000	445,919,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	748,269,000	644,351,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Loans	117,883,000	115,003,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	27,000	441,000
Current loans	1,728,871,000	1,493,075,000
Loans	1,728,898,000	1,493,516,000	1,153,189,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	27,000	0
Current loans	636,744,000	577,872,000
Loans	636,771,000	577,872,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	0
Current loans	26,519,000	30,138,000
Loans	26,519,000	30,138,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	0	441,000
Current loans	363,509,000	330,357,000
Loans	363,509,000	330,798,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	0	0
Current loans	652,054,000	520,754,000
Loans	652,054,000	520,754,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	0	0
Current loans	50,045,000	33,954,000
Loans	50,045,000	33,954,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	509,000	3,575,000
Current loans	335,940,000	449,605,000
Loans	336,449,000	453,180,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Past due loans	27,000	546,000
Current loans	77,105,000	117,885,000
Loans	77,132,000	118,431,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	27,000
Current loans	8,309,000	14,955,000
Loans	8,309,000	14,982,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	112,000	1,890,000
Current loans	86,843,000	113,231,000
Loans	86,955,000	115,121,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	353,000	835,000
Current loans	95,862,000	122,762,000
Loans	96,215,000	123,597,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	17,000	277,000
Current loans	67,821,000	80,772,000
Loans	67,838,000	81,049,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member]
Loans	313,273,000	331,031,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	118,047,000	140,646,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	195,226,000	190,385,000
Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	1,361,000	852,000
Current loans	154,289,000	122,219,000
Loans	155,650,000	123,071,000	$ 92,927,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	144,000	294,000
Current loans	69,687,000	67,522,000
Loans	69,831,000	67,816,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	1,217,000	558,000
Current loans	84,602,000	54,697,000
Loans	85,819,000	55,255,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	2,490,000	2,197,000
Current loans	155,133,000	205,763,000
Loans	157,623,000	207,960,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Past due loans	329,000	467,000
Current loans	47,887,000	72,363,000
Loans	48,216,000	72,830,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	2,161,000	1,730,000
Current loans	107,246,000	133,400,000
Loans	109,407,000	135,130,000
Loans past due 90 days or more still accruing interest	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Originated Loan [Member]
Past due loans	804,000	725,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Acquired Loan [Member]
Past due loans	1,575,000	1,981,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	0	432,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	0	432,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	62,000	626,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Past due loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	27,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	62,000	323,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	0	53,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	0	223,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	804,000	293,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	46,000	186,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	758,000	107,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	1,513,000	1,355,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Past due loans	258,000	395,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	1,255,000	960,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Originated Loan [Member]
Past due loans	247,000	203,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Acquired Loan [Member]
Past due loans	504,000	1,585,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	27,000	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	27,000	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	11,000	1,187,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Past due loans	11,000	5,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	0	425,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	0	703,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	0	54,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	220,000	203,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	98,000	108,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	122,000	95,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	493,000	398,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Past due loans	26,000	44,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	467,000	354,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Originated Loan [Member]
Past due loans	337,000	365,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Acquired Loan [Member]
Past due loans	920,000	2,206,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	0	9,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	0	9,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	436,000	1,762,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Past due loans	16,000	541,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Past due loans	50,000	1,142,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Past due loans	353,000	79,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residentia lRental Loan [Member]
Past due loans	17,000	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	337,000	356,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	337,000	356,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	484,000	444,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Past due loans	45,000	28,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	$ 439,000	$ 416,000