Note 3 - Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Loans	$ 2,881,493,000	$ 2,753,085,000
Originated Loan [Member]
Past due loans	115,000	658,000
Current loans	2,609,571,000	2,451,788,000
Loans	2,609,686,000	2,452,446,000
Loans past due 90 days or more still accruing interest	0	0
Acquired Loan [Member]
Past due loans	1,249,000	3,125,000
Current loans	270,558,000	297,514,000
Loans	271,807,000	300,639,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member]
Loans	2,464,555,000	2,360,106,000
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Loans	881,196,000	822,723,000
Commercial Portfolio Segment [Member] \| Vacant Land and Land Development and Residential Construction Loan [Member]
Loans	45,158,000	44,885,000
Commercial Portfolio Segment [Member] \| Real Estate Owner Occupied Loan [Member]
Loans	556,868,000	548,619,000
Commercial Portfolio Segment [Member] \| Real Estate Non Owner Occupied Loan [Member]
Loans	852,844,000	816,282,000
Commercial Portfolio Segment [Member] \| Real Estate Multi Family and Residential Rental Loan [Member]
Loans	128,489,000	127,597,000
Commercial Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	0	186,000
Current loans	2,274,931,000	2,151,812,000
Loans	2,274,931,000	2,151,998,000
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	0	186,000
Current loans	833,589,000	768,512,000
Loans	833,589,000	768,698,000
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	40,609,000	39,950,000
Loans	40,609,000	39,950,000
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	513,016,000	500,188,000
Loans	513,016,000	500,188,000
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	786,666,000	745,127,000
Loans	786,666,000	745,127,000
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	101,051,000	98,035,000
Loans	101,051,000	98,035,000
Loans past due 90 days or more still accruing interest	0	0
Commercial Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	349,000	1,147,000
Current loans	189,275,000	206,961,000
Loans	189,624,000	208,108,000
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	0	8,000
Current loans	47,607,000	54,017,000
Loans	47,607,000	54,025,000
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	122,000	19,000
Current loans	4,427,000	4,916,000
Loans	4,549,000	4,935,000
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	105,000	1,058,000
Current loans	43,747,000	47,373,000
Loans	43,852,000	48,431,000
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	122,000	62,000
Current loans	66,056,000	71,093,000
Loans	66,178,000	71,155,000
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	0	0
Current loans	27,438,000	29,562,000
Loans	27,438,000	29,562,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member]
Loans	416,938,000	392,979,000
Retail Portfolio Segment [Member] \| Home Equity and Other [Member]
Loans	81,320,000	85,439,000
Retail Portfolio Segment [Member] \| One to Four Family Mortgages [Member]
Loans	335,618,000	307,540,000
Retail Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	115,000	472,000
Current loans	334,640,000	299,976,000
Loans	334,755,000	300,448,000
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	7,000	44,000
Current loans	64,240,000	64,979,000
Loans	64,247,000	65,023,000
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	108,000	428,000
Current loans	270,400,000	234,997,000
Loans	270,508,000	235,425,000
Loans past due 90 days or more still accruing interest	0	0
Retail Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	900,000	1,978,000
Current loans	81,283,000	90,553,000
Loans	82,183,000	92,531,000
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	159,000	198,000
Current loans	16,914,000	20,218,000
Loans	17,073,000	20,416,000
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	741,000	1,780,000
Current loans	64,369,000	70,335,000
Loans	65,110,000	72,115,000
Loans past due 90 days or more still accruing interest	0	0
Financial Asset, 30 to 59 Days Past Due [Member] \| Originated Loan [Member]
Past due loans	7,000	521,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Acquired Loan [Member]
Past due loans	531,000	1,185,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	0	186,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Originated Loan [Member] \| Commercial and Industrial [Member]
Past due loans	0	186,000
Financial Asset, 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
Financial Asset, 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
Financial Asset, 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
Financial Asset, 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
Financial Asset, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	218,000	197,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Commercial and Industrial [Member]
Past due loans	0	8,000
Financial Asset, 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	122,000	19,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Real Estate Owner Occupied Loan [Member]
Past due loans	0	108,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Real Estate Non Owner Occupied Loan [Member]
Past due loans	96,000	62,000
Financial Asset, 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	0	0
Financial Asset, 30 to 59 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	7,000	335,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member] \| Home Equity and Other [Member]
Past due loans	7,000	44,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member] \| One to Four Family Mortgages [Member]
Past due loans	0	291,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	313,000	988,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member] \| Home Equity and Other [Member]
Past due loans	126,000	167,000
Financial Asset, 30 to 59 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member] \| One to Four Family Mortgages [Member]
Past due loans	187,000	821,000
Financial Asset, 60 to 89 Days Past Due [Member] \| Originated Loan [Member]
Past due loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] \| Acquired Loan [Member]
Past due loans	259,000	1,328,000
Financial Asset, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Originated Loan [Member] \| Commercial and Industrial [Member]
Past due loans	0	0
Financial Asset, 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
Financial Asset, 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
Financial Asset, 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
Financial Asset, 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
Financial Asset, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	105,000	950,000
Financial Asset, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Commercial and Industrial [Member]
Past due loans	0	0
Financial Asset, 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
Financial Asset, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Real Estate Owner Occupied Loan [Member]
Past due loans	105,000	950,000
Financial Asset, 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
Financial Asset, 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	0	0
Financial Asset, 60 to 89 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member] \| Home Equity and Other [Member]
Past due loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member] \| One to Four Family Mortgages [Member]
Past due loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	154,000	378,000
Financial Asset, 60 to 89 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member] \| Home Equity and Other [Member]
Past due loans	13,000	31,000
Financial Asset, 60 to 89 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member] \| One to Four Family Mortgages [Member]
Past due loans	141,000	347,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Originated Loan [Member]
Past due loans	108,000	137,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Acquired Loan [Member]
Past due loans	459,000	612,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Originated Loan [Member] \| Commercial and Industrial [Member]
Past due loans	0	0
Financial Asset, Equal to or 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
Financial Asset, Equal to or 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
Financial Asset, Equal to or 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
Financial Asset, Equal to or 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
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	26,000	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Commercial and Industrial [Member]
Past due loans	0	0
Financial Asset, Equal to or 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
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Real Estate Owner Occupied Loan [Member]
Past due loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Acquired Loan [Member] \| Real Estate Non Owner Occupied Loan [Member]
Past due loans	26,000	0
Financial Asset, Equal to or 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	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member]
Past due loans	108,000	137,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member] \| Home Equity and Other [Member]
Past due loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Originated Loan [Member] \| One to Four Family Mortgages [Member]
Past due loans	108,000	137,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member]
Past due loans	433,000	612,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member] \| Home Equity and Other [Member]
Past due loans	20,000	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] \| Retail Portfolio Segment [Member] \| Acquired Loan [Member] \| One to Four Family Mortgages [Member]
Past due loans	$ 413,000	$ 612,000

Note 3 - Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) - USD ($)

Jun. 30, 2019

Dec. 31, 2018

Loans

$ 2,881,493,000

$ 2,753,085,000

Originated Loan [Member]

Past due loans

115,000

658,000

Current loans

2,609,571,000