Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Components of Deferred Tax Assets [Abstract]
State income taxes, net of federal impact	$ 75,499	$ 65,917
Goodwill and intangibles	32,673	36,282
Unearned premiums	27,703	34,394
Lease liability	11,214	13,293
Accrued expenses	11,140	11,642
Share-based compensation	9,291	11,238
Deferred policy acquisition and ceding commission costs	7,043	11,190
Loss reserves	4,578	1,920
Other	8,732	11,188
Total deferred tax assets	187,873	197,064
Components of Deferred Tax Liabilities [Abstract]
Differences in fair value of financial instruments	9,087	5,708
Net unrealized gain on investments	70,057	29,303
Depreciation	13,029	12,803
Contingency reserve	216,122	137,983
Other	15,747	15,914
Total deferred tax liabilities	324,042	201,711
Less: Valuation allowance	77,728	66,437
Net deferred tax asset (liability)	$ (213,897)	$ (71,084)