Note 2 - Investment Securities - Gross Unrealized Losses, Investment Securities Portfolio (Details) $ in Thousands |
Dec. 31, 2023
USD ($)
|
Dec. 31, 2022
USD ($)
|
Available for sale securities, less than 12 months, number of investment positions |
39
|
376
|
Available for sale securities, less than 12 months, fair value |
$ 440,504
|
$ 2,673,207
|
Available for sale securities, less than 12 months, unrealized losses |
$ (8,946)
|
$ (225,835)
|
Available for sale securities, 12 months or longer, number of investment positions |
394
|
93
|
Available for sale securities, 12 months or longer, fair value |
$ 3,047,766
|
$ 757,794
|
Available for sale securities, 12 months or longer, unrealized losses |
$ (262,561)
|
$ (139,388)
|
Available for sale securities, total, number of investment positions |
433
|
469
|
Available for sale securities, total, fair value |
$ 3,488,270
|
$ 3,431,001
|
Available for sale securities, total, unrealized losses |
$ (271,507)
|
$ (365,223)
|
Held to Maturity securities, less than 12 months, number of investment positions |
27
|
200
|
Held to Maturity securities, less than 12 months, fair value |
$ 45,166
|
$ 821,756
|
Held to Maturity securities, less than 12 months, unrecognized losses |
$ (1,274)
|
$ (42,390)
|
Held to Maturity securities, 12 months or longer, number of investment positions |
165
|
2
|
Held to Maturity securities, 12 months or longer, fair value |
$ 739,440
|
$ 682
|
Held to Maturity securities, 12 months or longer, unrecognized losses |
$ (27,709)
|
$ (99)
|
Held to Maturity securities, total, number of investment positions |
192
|
202
|
Held to Maturity securities, total, fair value |
$ 784,606
|
$ 822,438
|
Held to Maturity securities, total, unrecognized losses |
$ (28,983)
|
$ (42,489)
|
Agency Residential MBS [Member] |
|
|
Available for sale securities, less than 12 months, number of investment positions |
1
|
107
|
Available for sale securities, less than 12 months, fair value |
$ 115
|
$ 279,139
|
Available for sale securities, less than 12 months, unrealized losses |
$ (2)
|
$ (24,222)
|
Available for sale securities, 12 months or longer, number of investment positions |
107
|
9
|
Available for sale securities, 12 months or longer, fair value |
$ 238,642
|
$ 6,110
|
Available for sale securities, 12 months or longer, unrealized losses |
$ (18,700)
|
$ (823)
|
Available for sale securities, total, number of investment positions |
108
|
116
|
Available for sale securities, total, fair value |
$ 238,757
|
$ 285,249
|
Available for sale securities, total, unrealized losses |
$ (18,702)
|
$ (25,045)
|
Held to Maturity securities, less than 12 months, number of investment positions |
1
|
97
|
Held to Maturity securities, less than 12 months, fair value |
$ 0
|
$ 95,814
|
Held to Maturity securities, less than 12 months, unrecognized losses |
$ 0
|
$ (7,404)
|
Held to Maturity securities, 12 months or longer, number of investment positions |
93
|
2
|
Held to Maturity securities, 12 months or longer, fair value |
$ 72,376
|
$ 682
|
Held to Maturity securities, 12 months or longer, unrecognized losses |
$ (5,270)
|
$ (99)
|
Held to Maturity securities, total, number of investment positions |
94
|
99
|
Held to Maturity securities, total, fair value |
$ 72,376
|
$ 96,496
|
Held to Maturity securities, total, unrecognized losses |
$ (5,270)
|
$ (7,503)
|
US Government Agencies Debt Securities [Member] |
|
|
Available for sale securities, less than 12 months, number of investment positions |
2
|
22
|
Available for sale securities, less than 12 months, fair value |
$ 9,746
|
$ 289,067
|
Available for sale securities, less than 12 months, unrealized losses |
$ (15)
|
$ (15,486)
|
Available for sale securities, 12 months or longer, number of investment positions |
19
|
0
|
Available for sale securities, 12 months or longer, fair value |
$ 278,265
|
$ 0
|
Available for sale securities, 12 months or longer, unrealized losses |
$ (13,836)
|
$ 0
|
Available for sale securities, total, number of investment positions |
21
|
22
|
Available for sale securities, total, fair value |
$ 288,011
|
$ 289,067
|
Available for sale securities, total, unrealized losses |
$ (13,851)
|
$ (15,486)
|
US States and Political Subdivisions Debt Securities [Member] |
|
|
Available for sale securities, less than 12 months, number of investment positions |
2
|
56
|
Available for sale securities, less than 12 months, fair value |
$ 2,280
|
$ 65,633
|
Available for sale securities, less than 12 months, unrealized losses |
$ (15)
|
$ (1,902)
|
Available for sale securities, 12 months or longer, number of investment positions |
50
|
8
|
Available for sale securities, 12 months or longer, fair value |
$ 57,614
|
$ 3,265
|
Available for sale securities, 12 months or longer, unrealized losses |
$ (1,423)
|
$ (177)
|
Available for sale securities, total, number of investment positions |
52
|
64
|
Available for sale securities, total, fair value |
$ 59,894
|
$ 68,898
|
Available for sale securities, total, unrealized losses |
$ (1,438)
|
$ (2,079)
|
Held to Maturity securities, less than 12 months, number of investment positions |
23
|
54
|
Held to Maturity securities, less than 12 months, fair value |
$ 18,599
|
$ 53,536
|
Held to Maturity securities, less than 12 months, unrecognized losses |
$ (90)
|
$ (538)
|
Held to Maturity securities, 12 months or longer, number of investment positions |
26
|
0
|
Held to Maturity securities, 12 months or longer, fair value |
$ 25,466
|
$ 0
|
Held to Maturity securities, 12 months or longer, unrecognized losses |
$ (245)
|
$ 0
|
Held to Maturity securities, total, number of investment positions |
49
|
54
|
Held to Maturity securities, total, fair value |
$ 44,065
|
$ 53,536
|
Held to Maturity securities, total, unrecognized losses |
$ (335)
|
$ (538)
|
Corporate Debt Securities [Member] |
|
|
Available for sale securities, less than 12 months, number of investment positions |
0
|
133
|
Available for sale securities, less than 12 months, fair value |
$ 0
|
$ 1,521,294
|
Available for sale securities, less than 12 months, unrealized losses |
$ 0
|
$ (170,453)
|
Available for sale securities, 12 months or longer, number of investment positions |
151
|
56
|
Available for sale securities, 12 months or longer, fair value |
$ 1,894,602
|
$ 555,727
|
Available for sale securities, 12 months or longer, unrealized losses |
$ (220,035)
|
$ (137,190)
|
Available for sale securities, total, number of investment positions |
151
|
189
|
Available for sale securities, total, fair value |
$ 1,894,602
|
$ 2,077,021
|
Available for sale securities, total, unrealized losses |
$ (220,035)
|
$ (307,643)
|
Held to Maturity securities, less than 12 months, number of investment positions |
3
|
49
|
Held to Maturity securities, less than 12 months, fair value |
$ 26,567
|
$ 672,406
|
Held to Maturity securities, less than 12 months, unrecognized losses |
$ (1,184)
|
$ (34,448)
|
Held to Maturity securities, 12 months or longer, number of investment positions |
46
|
0
|
Held to Maturity securities, 12 months or longer, fair value |
$ 641,598
|
$ 0
|
Held to Maturity securities, 12 months or longer, unrecognized losses |
$ (22,194)
|
$ 0
|
Held to Maturity securities, total, number of investment positions |
49
|
49
|
Held to Maturity securities, total, fair value |
$ 668,165
|
$ 672,406
|
Held to Maturity securities, total, unrecognized losses |
$ (23,378)
|
$ (34,448)
|
Collateralized Debt Obligations [Member] |
|
|
Available for sale securities, less than 12 months, number of investment positions |
34
|
58
|
Available for sale securities, less than 12 months, fair value |
$ 428,363
|
$ 518,074
|
Available for sale securities, less than 12 months, unrealized losses |
$ (8,914)
|
$ (13,772)
|
Available for sale securities, 12 months or longer, number of investment positions |
67
|
20
|
Available for sale securities, 12 months or longer, fair value |
$ 578,643
|
$ 192,692
|
Available for sale securities, 12 months or longer, unrealized losses |
$ (8,567)
|
$ (1,198)
|
Available for sale securities, total, number of investment positions |
101
|
78
|
Available for sale securities, total, fair value |
$ 1,007,006
|
$ 710,766
|
Available for sale securities, total, unrealized losses |
$ (17,481)
|
$ (14,970)
|