Note 3 - Loans and Allowance for Loan Losses (Details Textual) - USD ($)		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Loans and Leases Receivable, Net of Deferred Income, Total		$ 3,453,459,000		$ 3,193,470,000
Impaired Financing Receivable, Interest Income, Accrual Method, Total		1,500,000		1,300,000		$ 1,300,000
Loans and Leases Receivable, Nonaccrual Loans, Interest Income Recognized		100,000		100,000		100,000
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans		$ 100,000		200,000		$ 100,000
Minimum Number of Days Past Due at Period End For Loans Modified as Troubled Debt Restructurings (Day)		30 days
Commercial Portfolio Segment [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		$ 2,950,424,000		2,793,962,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans and Leases Receivable, Net of Deferred Income, Total	[1]	1,137,419,000		1,145,423,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Grades 1-4 [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		729,224,000	[2]	828,706,000	[3]
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | SBA, CARES Act, Paycheck Protection Program [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		40,100,000		365,000,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | SBA, CARES Act, Paycheck Protection Program [Member] | Grades 1-4 [Member]
Loans and Leases Receivable, Net of Deferred Income, Total		$ 40,100,000		$ 365,000,000

[1] For December 31, 2021, and December 31, 2020, includes $40.1 million and $365 million in loans originated under the Paycheck Protection Program, respectively.

[2] Included in Commercial and Industrial Loans Grades 1 - 4 are $40.1 million of loans originated under the Paycheck Protection Program.

[3] Included in Commercial and Industrial Loans Grades 1 – 4 are $365 million of loans originated under the Paycheck Protection Program.