Note 19 - Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net premiums earned—insurance (Note 8)	$ 301,486		$ 281,185		$ 299,166		$ 263,512		$ 261,682		$ 258,431		$ 251,344		$ 242,550		$ 1,145,349		$ 1,014,007		$ 932,773
Services revenue (Note 4)	40,031		42,509		39,303		32,753		38,414		36,566		36,828		33,164		154,596		144,972		155,103
Net investment income (Note 6)	41,432		42,756		43,761		43,847		42,051		38,995		37,473		33,956		171,796		152,475		127,248
Net gains (losses) on investments and other financial instruments	4,257		13,009		12,540		21,913		(11,705)		(4,480)		(7,404)		(18,887)		51,719		(42,476)		3,621
Provision for losses	34,619		29,231		47,427		20,754		27,140		20,881		19,337		37,283		132,031		104,641		135,154
Policy acquisition costs	6,783		6,435		6,203		5,893		6,485		5,667		5,996		7,117		25,314		25,265		24,277
Cost of services	27,278		29,044		27,845		24,157		24,939		25,854		24,205		23,126		108,324		98,124		104,599
Other operating expenses	80,894		76,384		70,046		78,805		77,266		70,125		70,184		63,243		306,129		280,818		267,321
Restructuring and other exit costs									113		4,464		925		551		0		6,053		17,268
Loss on extinguishment of debt	0		5,940		16,798		0
Impairment of goodwill	4,828		0		0		0										4,828		0		184,374
Amortization and impairment of other acquired intangible assets	15,823		2,139		2,139		2,187		3,461		3,472		2,748		2,748		22,288		12,429		27,671
Net income	$ 161,184		$ 173,438		$ 166,730		$ 170,957		$ 139,779		$ 142,797		$ 208,949		$ 114,486		$ 672,309		$ 606,011		$ 121,088
Diluted net income per share	$ 0.79	[1]	$ 0.83	[1]	$ 0.78	[1]	$ 0.78	[1]	$ 0.64	[1]	$ 0.66	[1]	$ 0.96	[1]	$ 0.52	[1]	$ 3.20	[1]	$ 2.77	[1]	$ 0.55
Weighted-average number of common and common equivalent shares outstanding—diluted	205,165		208,691		213,603		218,343		217,883		217,902		217,830		219,883		210,340		218,553		220,406

[1] Diluted net income per share is computed independently for each period presented. Consequently, the sum of the quarters may not equal the total net income per share for the year.