Note 7 - Comprehensive (Loss) Income - Reclassification out of Accumulated Other Comprehensive (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest income (expense) on cash flow hedges	$ 62,357	$ 78,161	$ 193,284	$ 224,110
Income tax expense	7,228	10,425	23,742	33,665
Net income	21,407	28,915	67,730	92,654
Other components of net periodic pension expense	(25)	(143)	(76)	(429)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net income	3,299	823	8,943	330
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Interest income (expense) on cash flow hedges	4,793	1,178	13,013	524
Income tax expense	22	5	67	14
Net income	(52)	(12)	(155)	(35)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Income tax expense	(1,442)	(343)	(3,915)	(159)
Net income	3,351	835	9,098	365
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Other components of net periodic pension expense	$ (74)	$ (17)	$ (222)	$ (49)