Note 2 - Investment Securities - Gross Unrealized Losses, Investment Securities Portfolio (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Available for sale securities, less than 12 months, number of investment positions	88	40
Available for sale securities, less than 12 months, fair value	$ 911,513	$ 269,526
Available for sale securities, less than 12 months, unrealized losses	$ (10,215)	$ (1,100)
Available for sale securities, 12 months or longer, number of investment positions	13	2
Available for sale securities, 12 months or longer, fair value	$ 52,358	$ 14,980
Available for sale securities, 12 months or longer, unrealized losses	$ (200)	$ (42)
Available for sale securities, total, number of investment positions	101	42
Available for sale securities, total, fair value	$ 963,871	$ 284,506
Available for sale securities, total, unrealized losses	$ (10,415)	$ (1,142)
Held to Maturity securities, less than 12 months, number of investment positions	1
Held to Maturity securities, less than 12 months, fair value	$ 542
Held to Maturity securities, less than 12 months, unrecognized losses	$ (19)
Held to Maturity securities, 12 months or longer, number of investment positions	3
Held to Maturity securities, 12 months or longer, fair value	$ 530
Held to Maturity securities, 12 months or longer, unrecognized losses	$ (18)
Held to Maturity securities, total, number of investment positions	4
Held to Maturity securities, total, fair value	$ 1,072
Held to Maturity securities, total, unrecognized losses	$ (37)
Agency Residential MBS [Member]
Available for sale securities, less than 12 months, number of investment positions	7	1
Available for sale securities, less than 12 months, fair value	$ 8,900	$ 96
Available for sale securities, less than 12 months, unrealized losses	$ (37)	$ (1)
Available for sale securities, 12 months or longer, number of investment positions	2	1
Available for sale securities, 12 months or longer, fair value	$ 47	$ 17
Available for sale securities, 12 months or longer, unrealized losses	$ 0	$ 0
Available for sale securities, total, number of investment positions	9	2
Available for sale securities, total, fair value	$ 8,947	$ 113
Available for sale securities, total, unrealized losses	$ (37)	$ (1)
Held to Maturity securities, less than 12 months, number of investment positions	0	3
Held to Maturity securities, less than 12 months, fair value	$ 0	$ 377
Held to Maturity securities, less than 12 months, unrecognized losses	$ 0	$ (1)
Held to Maturity securities, 12 months or longer, number of investment positions	3	3
Held to Maturity securities, 12 months or longer, fair value	$ 530	$ 788
Held to Maturity securities, 12 months or longer, unrecognized losses	$ (18)	$ (31)
Held to Maturity securities, total, number of investment positions	3	6
Held to Maturity securities, total, fair value	$ 530	$ 1,165
Held to Maturity securities, total, unrecognized losses	$ (18)	$ (32)
US Government Agencies Debt Securities [Member]
Available for sale securities, less than 12 months, number of investment positions	0	1
Available for sale securities, less than 12 months, fair value	$ 0	$ 154
Available for sale securities, less than 12 months, unrealized losses	$ 0	$ 0
Available for sale securities, 12 months or longer, number of investment positions	1	0
Available for sale securities, 12 months or longer, fair value	$ 119	$ 0
Available for sale securities, 12 months or longer, unrealized losses	$ 0	$ 0
Available for sale securities, total, number of investment positions	1	1
Available for sale securities, total, fair value	$ 119	$ 154
Available for sale securities, total, unrealized losses	$ 0	$ 0
Non-agency Residential MBS [Member]
Held to Maturity securities, less than 12 months, number of investment positions	1
Held to Maturity securities, less than 12 months, fair value	$ 542
Held to Maturity securities, less than 12 months, unrecognized losses	$ (19)
Held to Maturity securities, 12 months or longer, number of investment positions	0
Held to Maturity securities, 12 months or longer, fair value	$ 0
Held to Maturity securities, 12 months or longer, unrecognized losses	$ 0
Held to Maturity securities, total, number of investment positions	1
Held to Maturity securities, total, fair value	$ 542
Held to Maturity securities, total, unrecognized losses	$ (19)
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities, less than 12 months, number of investment positions	6	2
Available for sale securities, less than 12 months, fair value	$ 2,859	$ 692
Available for sale securities, less than 12 months, unrealized losses	$ (27)	$ (1)
Available for sale securities, 12 months or longer, number of investment positions	2	0
Available for sale securities, 12 months or longer, fair value	$ 669	$ 0
Available for sale securities, 12 months or longer, unrealized losses	$ (2)	$ 0
Available for sale securities, total, number of investment positions	8	2
Available for sale securities, total, fair value	$ 3,528	$ 692
Available for sale securities, total, unrealized losses	$ (29)	$ (1)
Debt Security, Corporate, US [Member]
Available for sale securities, less than 12 months, number of investment positions	56	0
Available for sale securities, less than 12 months, fair value	$ 691,555	$ 0
Available for sale securities, less than 12 months, unrealized losses	$ (9,630)	$ 0
Available for sale securities, 12 months or longer, number of investment positions	0	1
Available for sale securities, 12 months or longer, fair value	$ 0	$ 14,963
Available for sale securities, 12 months or longer, unrealized losses	$ 0	$ (42)
Available for sale securities, total, number of investment positions	56	1
Available for sale securities, total, fair value	$ 691,555	$ 14,963
Available for sale securities, total, unrealized losses	$ (9,630)	$ (42)
Collateralized Loan Obligations [Member]
Available for sale securities, less than 12 months, number of investment positions	19
Available for sale securities, less than 12 months, fair value	$ 208,199
Available for sale securities, less than 12 months, unrealized losses	$ (521)
Available for sale securities, 12 months or longer, number of investment positions	8
Available for sale securities, 12 months or longer, fair value	$ 51,523
Available for sale securities, 12 months or longer, unrealized losses	$ (198)
Available for sale securities, total, number of investment positions	27
Available for sale securities, total, fair value	$ 259,722
Available for sale securities, total, unrealized losses	$ (719)
Collateralized Debt Obligations [Member]
Available for sale securities, less than 12 months, number of investment positions		36
Available for sale securities, less than 12 months, fair value		$ 268,584
Available for sale securities, less than 12 months, unrealized losses		$ (1,098)
Available for sale securities, 12 months or longer, number of investment positions		0
Available for sale securities, 12 months or longer, fair value		$ 0
Available for sale securities, 12 months or longer, unrealized losses		$ 0
Available for sale securities, total, number of investment positions		36
Available for sale securities, total, fair value		$ 268,584
Available for sale securities, total, unrealized losses		$ (1,098)