Note 6 - Investments - Net Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on investments	$ 4,266	$ 7,024	$ 4,084	$ 18,663
Impairment losses due to intent to sell	0	(779)	0	(1,401)
Net decrease (increase) in expected credit losses	608	(2,782)	918	(2,782)
Net unrealized gain (losses) on investments	8,036	24,948	5,517	(1,897)
Total net gains (losses) on investments	12,910	28,411	10,519	12,583
Fixed-maturities available for sale
Gain (Loss) on Securities [Line Items]
Fixed maturities available for sale, net realized gain (loss)	2,376	6,974	1,586	18,221
Gross investment gains from sales and redemptions	9,597	8,304	13,714	20,203
Gross investment losses from sales and redemptions	(7,221)	(1,330)	(12,128)	(1,982)
Trading Securities
Gain (Loss) on Securities [Line Items]
Trading securities, net realized gain (loss)	(112)	(45)	391	4
Equity securities
Gain (Loss) on Securities [Line Items]
Equity securities, net realized gain (loss)	(227)	51	(227)	361
Other investments
Gain (Loss) on Securities [Line Items]
Other investments, net realized gain (loss)	$ 2,229	$ 44	$ 2,334	$ 77