Note 13 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands		Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale		$ 1,541,250	$ 1,473,348
Equity securities		27,011	22,158
Warrants		71,840	90,451
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale		269,698	240,500
Equity securities		27,011	22,158
Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale		1,271,552	1,232,848
Equity securities		0	0
Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale		0	0
Equity securities		0	0
Estimate of Fair Value Measurement [Member]
Cash and due from banks		252,048	195,440
Short-term investments.		881,282	966,962
Debt Securities, Available-for-Sale		1,541,250	1,473,348
Loans, net	[1]	18,195,465	17,944,588
Equity securities		27,011	22,158
Investment in Federal Home Loan Bank stock		17,250	17,250
Deposits		18,798,687	18,572,387
Advances from Federal Home Loan Bank		358,334	482,737
Other borrowings		18,461	18,385
Long-term debt		61,939	68,231
Estimate of Fair Value Measurement [Member] | Warrants [Member]
Warrants		0	50
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and due from banks		252,048	195,440
Short-term investments.		881,282	966,962
Debt Securities, Available-for-Sale		269,698	240,500
Loans, net	[1]	0	0
Equity securities		27,011	22,158
Investment in Federal Home Loan Bank stock		0	0
Deposits		0	0
Advances from Federal Home Loan Bank		0	0
Other borrowings		0	0
Long-term debt		0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Warrants [Member]
Warrants			0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and due from banks		0	0
Short-term investments.		0	0
Debt Securities, Available-for-Sale		1,271,552	1,232,848
Loans, net	[1]	0	0
Equity securities		0	0
Investment in Federal Home Loan Bank stock		17,250	17,250
Deposits		0	0
Advances from Federal Home Loan Bank		358,334	482,737
Other borrowings		0	0
Long-term debt		61,939	68,231
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Warrants [Member]
Warrants			0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and due from banks		0	0
Short-term investments.		0	0
Debt Securities, Available-for-Sale		0	0
Loans, net	[1]	18,195,465	17,944,588
Equity securities		0	0
Investment in Federal Home Loan Bank stock		0	0
Deposits		18,798,687	18,572,387
Advances from Federal Home Loan Bank		0	0
Other borrowings		18,461	18,385
Long-term debt		$ 0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Warrants [Member]
Warrants			$ 50

[1] In accordance with the prospective adoption of ASU 2016-01, the fair value of loans as of December 31, 2019 & 2018 was measured using an exit price notion.