Note 3 - Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Loans	$ 2,527,281,000	$ 2,378,620,000
Originated Loan [Member]
Past due loans	1,736,000	1,388,000
Current loans	2,077,139,000	1,883,160,000
Loans	2,078,875,000	1,884,548,000
Loans past due 90 days or more still accruing interest	61,000	0
Acquired Loan [Member]
Past due loans	2,764,000	2,999,000
Current loans	445,642,000	491,073,000
Loans	448,406,000	494,072,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member]
Loans	2,198,593,000	2,065,347,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans	780,816,000	713,903,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	29,027,000	34,828,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans	491,633,000	450,464,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	783,036,000	748,269,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	114,081,000	117,883,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	1,450,000	27,000
Current loans	1,886,680,000	1,728,871,000
Loans	1,888,130,000	1,728,898,000
Loans past due 90 days or more still accruing interest	49,000	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	1,450,000	27,000
Current loans	706,795,000	636,744,000
Loans	708,245,000	636,771,000
Loans past due 90 days or more still accruing interest	49,000	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	21,654,000	26,519,000
Loans	21,654,000	26,519,000
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	0
Current loans	411,547,000	363,509,000
Loans	411,547,000	363,509,000
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	696,499,000	652,054,000
Loans	696,499,000	652,054,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Past due loans	0	0
Current loans	50,185,000	50,045,000
Loans	50,185,000	50,045,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	351,000	509,000
Current loans	310,112,000	335,940,000
Loans	310,463,000	336,449,000
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	59,000	27,000
Current loans	72,512,000	77,105,000
Loans	72,571,000	77,132,000
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	0
Current loans	7,373,000	8,309,000
Loans	7,373,000	8,309,000
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	202,000	112,000
Current loans	79,884,000	86,843,000
Loans	80,086,000	86,955,000
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	0	353,000
Current loans	86,537,000	95,862,000
Loans	86,537,000	96,215,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Past due loans	90,000	17,000
Current loans	63,806,000	67,821,000
Loans	63,896,000	67,838,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member]
Loans	328,688,000	313,273,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans	107,991,000	118,047,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans	220,697,000	195,226,000
Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	286,000	1,361,000
Current loans	190,459,000	154,289,000
Loans	190,745,000	155,650,000
Loans past due 90 days or more still accruing interest	12,000	0
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	77,000	144,000
Current loans	69,711,000	69,687,000
Loans	69,788,000	69,831,000
Loans past due 90 days or more still accruing interest	12,000	0
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Past due loans	209,000	1,217,000
Current loans	120,748,000	84,602,000
Loans	120,957,000	85,819,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	2,413,000	2,490,000
Current loans	135,530,000	155,133,000
Loans	137,943,000	157,623,000
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	346,000	329,000
Current loans	37,857,000	47,887,000
Loans	38,203,000	48,216,000
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	2,067,000	2,161,000
Current loans	97,673,000	107,246,000
Loans	99,740,000	109,407,000
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	285,000	804,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Acquired Loan [Member]
Past due loans	1,298,000	1,575,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	225,000	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	225,000	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	0
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 Residential Rental 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	180,000	62,000
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	0
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	164,000	62,000
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	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Past due loans	16,000	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	60,000	804,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	60,000	46,000
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	0	758,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	1,118,000	1,513,000
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	258,000
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	860,000	1,255,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Originated Loan [Member]
Past due loans	5,000	247,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Acquired Loan [Member]
Past due loans	415,000	504,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	0	27,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Past due loans	0	27,000
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 Residential Rental 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	81,000	11,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Past due loans	18,000	11,000
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	0
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	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Past due loans	63,000	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	5,000	220,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Past due loans	5,000	98,000
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	0	122,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	334,000	493,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Past due loans	67,000	26,000
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	267,000	467,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Originated Loan [Member]
Past due loans	1,446,000	337,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Acquired Loan [Member]
Past due loans	1,051,000	920,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	1,225,000	0
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	1,225,000	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	0
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 Residential Rental 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	90,000	436,000
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	41,000	16,000
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	38,000	50,000
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	0	353,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Past due loans	11,000	17,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Originated Loan [Member]
Past due loans	221,000	337,000
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	12,000	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	209,000	337,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Acquired Loan [Member]
Past due loans	961,000	484,000
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	21,000	45,000
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	$ 940,000	$ 439,000