Note 13 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands		Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-Sale, Total		$ 1,414,411	$ 1,127,309
Equity securities		23,123	22,319
Warrants		98,498	10,090
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-Sale, Total		241,400	0
Equity securities		23,123	22,319
Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-Sale, Total		1,173,011	1,127,309
Equity securities		0	0
Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-Sale, Total		0	0
Equity securities		0	0
Estimate of Fair Value Measurement [Member]
Cash and due from banks		200,051	134,141
Short-term investments		1,063,294	2,315,563
Debt Securities, Available-for-Sale, Total		1,414,411	1,127,309
Loans, net	[1]	17,676,365	16,499,869
Equity securities		23,123	22,319
Investment in Federal Home Loan Bank stock		17,250	17,250
Deposits		18,573,442	18,051,720
Advances from Federal Home Loan Bank		359,416	21,279
Other borrowings		18,357	18,945
Long-term debt		56,317	62,274
Estimate of Fair Value Measurement [Member] | Warrants [Member]
Warrants		46	23
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and due from banks		200,051	134,141
Short-term investments		1,063,294	2,315,563
Debt Securities, Available-for-Sale, Total		241,400	0
Loans, net	[1]	0	0
Equity securities		23,123	22,319
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	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, Total		1,173,011	1,127,309
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		359,416	21,279
Other borrowings		0	0
Long-term debt		56,317	62,274
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Warrants [Member]
Warrants		0	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, Total		0	0
Loans, net	[1]	17,676,365	16,499,869
Equity securities		0	0
Investment in Federal Home Loan Bank stock		0	0
Deposits		18,573,442	18,051,720
Advances from Federal Home Loan Bank		0	0
Other borrowings		18,357	18,945
Long-term debt		0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Warrants [Member]
Warrants		$ 46	$ 23

[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.