Note 8 - Other Assets Components of Other Assets (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Other Assets [Abstract]
Deposit with the IRS (Note 9)		$ 88,557		$ 88,557		$ 88,557
Corporate-owned life insurance		82,800		82,800		85,862
Internal-use software	[1]	51,191		51,191		48,751
Property and equipment	[2]	38,060		38,060		38,291
Accrued investment income		34,430		34,430		31,389
Loaned securities		34,364		34,364		27,964
Unbilled receivables		19,580		19,580		22,257
Deferred policy acquisition costs		16,922		16,922		16,987
Reinsurance recoverables		13,542		13,542		8,492
Other		35,826		35,826		39,299
Total other assets		415,272		415,272		407,849
Capitalized Computer Software, Accumulated Amortization		57,200		57,200		48,400
Capitalized Computer Software, Amortization		2,900	$ 2,700	8,600	$ 7,900
Property and Equipment, Owned, Accumulated Depreciation		61,000		61,000		$ 57,600
Depreciation expense		$ 2,100	$ 1,900	$ 5,900	$ 4,900

[1] Internal-use software at cost, less accumulated amortization of $57.2 million and $48.4 million at September 30, 2018 and December 31, 2017, respectively. Amortization expense was $2.9 million and $2.7 million for the three-month periods ended September 30, 2018 and 2017, respectively, and $8.6 million and $7.9 million for the nine-month periods ended September 30, 2018 and 2017, respectively.

[2] Property and equipment at cost, less accumulated depreciation of $61.0 million and $57.6 million at September 30, 2018 and December 31, 2017, respectively. Depreciation expense was $2.1 million and $1.9 million for the three-month periods ended September 30, 2018 and 2017, respectively, and $5.9 million and $4.9 million for the nine-month periods ended September 30, 2018 and 2017, respectively.