Note 13 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022
Securities available-for-sale		$ 1,487,321	$ 1,473,348
Equity securities		37,674	22,158
Warrants		81,760	90,451
Foreign exchange contracts with gain		249,696	72,996
Foreign exchange contracts with gain, fair value		648	448
Interest rate swaps		1,402,060	817,615
Interest rate swaps, fair value		81,759	44,443
Foreign exchange contracts with loss		49,196	170,213
Foreign exchange contracts with loss, fair value		632	942
Interest rate swaps		640,397	595,426
Interest rate swaps, fair value		50,017	51,864
Commitments to extend credit		3,896,018	3,630,304
Commitments to extend credit, fair value		(15,490)	(14,797)
Standby letters of credit		333,550	315,821
Standby letters of credit, fair value		(2,727)	(2,738)
Other letters of credit		10,515	29,416
Other letters of credit, fair value		(9)	(33)
Reported Value Measurement [Member]
Cash and due from banks		187,886	195,440
Short-term investments		1,294,379	966,962
Securities available-for-sale		1,487,321	1,473,348
Loans, net		18,788,188	18,100,898
Equity securities		37,674	22,158
Investment in Federal Home Loan Bank stock		25,242	17,250
Deposits		19,097,003	18,505,279
Advances from Federal Home Loan Bank		815,000	485,000
Other borrowings		22,428	22,600
Long-term debt		119,136	119,136
Reported Value Measurement [Member] | Warrants [Member]
Warrants		0	50
Estimate of Fair Value Measurement [Member]
Cash and due from banks		187,886	195,440
Short-term investments		1,294,379	966,962
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

[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.