Note 9 - Other Assets - Components of Other Assets (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2021 USD ($) numberOfLeases	Dec. 31, 2020 USD ($)
Prepaid federal income taxes (Note 10)	$ 275,623	$ 210,889
Prepaid Reinsurance Premiums	225,727	267,638
Loaned securities (Note 5)	130,850	57,499
Company-owned life insurance	112,638	115,586
Right-of-use assets (Note 13)	34,662	32,985
Other	35,761	30,488
Other Assets	815,261	$ 715,085
Impairment of Leasehold	$ 3,500
Number of Corporate Headquarter Leases | numberOfLeases	2
Corporate headquarters
Right-of-use assets (Note 13)	$ 28,400