Note 3 - Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) - USD ($)		Jun. 30, 2021	Dec. 31, 2020
Loans and Leases Receivable, Net of Deferred Income, Total		$ 3,248,841,000	$ 3,193,470,000
Loans past due 90 days or more still accruing interest		0	0
Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		2,810,309,000	2,793,962,000
Loans past due 90 days or more still accruing interest		0	0
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	[1]	1,103,807,000	1,145,423,000
Loans past due 90 days or more still accruing interest		0	0
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		43,111,000	55,055,000
Loans past due 90 days or more still accruing interest		0	0
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		550,504,000	529,953,000
Loans past due 90 days or more still accruing interest		0	0
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		950,993,000	917,436,000
Loans past due 90 days or more still accruing interest		0	0
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		161,894,000	146,095,000
Loans past due 90 days or more still accruing interest		0	0
Retail Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		438,532,000	399,508,000
Loans past due 90 days or more still accruing interest		0	0
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		58,240,000	61,620,000
Loans past due 90 days or more still accruing interest		0	0
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		380,292,000	337,888,000
Loans past due 90 days or more still accruing interest		0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		250,000	1,520,000
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	261,000
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	261,000
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		250,000	1,259,000
Financial Asset, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		50,000	112,000
Financial Asset, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		200,000	1,147,000
Financial Asset, 60 to 89 Days Past Due [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		942,000	681,000
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		887,000	369,000
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		456,000	172,000
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		431,000	197,000
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		55,000	312,000
Financial Asset, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	65,000
Financial Asset, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		55,000	247,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		742,000	840,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		606,000	444,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		606,000	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	421,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	23,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		136,000	396,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		35,000	54,000
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		101,000	342,000
Financial Asset, Past Due [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		1,934,000	3,041,000
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		1,493,000	1,074,000
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		1,062,000	433,000
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		431,000	618,000
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	23,000
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		0	0
Financial Asset, Past Due [Member] | Retail Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		441,000	1,967,000
Financial Asset, Past Due [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		85,000	231,000
Financial Asset, Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		356,000	1,736,000
Financial Asset, Not Past Due [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		3,246,907,000	3,190,429,000
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		2,808,816,000	2,792,888,000
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		1,102,745,000	1,144,990,000
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		43,111,000	55,055,000
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		550,073,000	529,335,000
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		950,993,000	917,413,000
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		161,894,000	146,095,000
Financial Asset, Not Past Due [Member] | Retail Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		438,091,000	397,541,000
Financial Asset, Not Past Due [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		58,155,000	61,389,000
Financial Asset, Not Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		$ 379,936,000	$ 336,152,000

[1] Includes $246 million and $365 million in loans originated under the Paycheck Protection Program for June 30, 2021 and December 31, 2020, respectively.