Note 13 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale		$ 1,487,321	$ 1,473,348
Equity securities		37,674	22,158
Warrants		81,760	90,451
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale		272,038	240,500
Equity securities		37,674	22,158
Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale		1,215,283	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		187,886	195,440
Short-term investments		1,294,379	966,962
Debt Securities, Available-for-Sale		1,487,321	1,473,348
Loans, net	[1]	18,647,234	17,944,588
Equity securities		37,674	22,158
Investment in Federal Home Loan Bank stock		25,242	17,250
Deposits		19,216,932	18,572,387
Advances from Federal Home Loan Bank		811,425	482,737
Other borrowings		18,177	18,385
Long-term debt		66,685	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		187,886	195,440
Short-term investments		1,294,379	966,962
Debt Securities, Available-for-Sale		272,038	240,500
Loans, net	[1]	0	0
Equity securities		37,674	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		1,215,283	1,232,848
Loans, net	[1]	0	0
Equity securities		0	0
Investment in Federal Home Loan Bank stock		25,242	17,250
Deposits		0	0
Advances from Federal Home Loan Bank		811,425	482,737
Other borrowings		0	0
Long-term debt		66,685	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]	18,647,234	17,944,588
Equity securities		0	0
Investment in Federal Home Loan Bank stock		0	0
Deposits		19,216,932	18,572,387
Advances from Federal Home Loan Bank		0	0
Other borrowings		18,177	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.