Note 11 - Investments in Marketable Securities - Amortized Cost and Estimated Fair Value of Debt Securities as Available for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Within 1 year, cost	$ 34,690	$ 49,694
Within 1 year, fair value	34,792	49,863
1 to 5 years, cost	97,382	99,143
1 to 5 years, fair value	99,947	103,002
6 to 10 years, cost	38,060	34,326
6 to 10 years, fair value	38,901	36,685
Over 10 years, cost	497	274
Over 10 years, fair value	481	285
Cost	170,629	183,437
Fair Value	$ 174,121	$ 189,835

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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