Note 6 - Investments Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Investment Income [Line Items]
Gross investment income	$ 179,932	$ 159,955	$ 133,648
Investment expenses	(8,136)	(7,480)	(6,400)
Net investment income	171,796	152,475	127,248
Fixed-maturities available for sale
Net Investment Income [Line Items]
Gross investment income	155,104	141,552	122,890
Equity securities
Net Investment Income [Line Items]
Gross investment income	7,028	7,157	4,318
Short-term investments
Net Investment Income [Line Items]
Gross investment income	17,255	10,270	5,453
Other investments
Net Investment Income [Line Items]
Gross investment income	$ 545	$ 976	$ 987

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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