Note 14 - Accumulated Other Comprehensive Income (Loss) Rollforward of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Other Comprehensive Income, Net of Tax [Abstract]
AOCI, Net of Tax, Balance at beginning of period		$ 110,488
Unrealized holding gains (losses) arising during the period		(72,293)	$ 78,023
Less: Reclassification adjustment for net gains (losses) included in net income (loss)		8,394	(391)
Other comprehensive income (loss), net of tax		(80,687)	78,414
AOCI, Net of Tax, Balance at end of period		29,801
Other Comprehensive Income
Other Comprehensive Income, before Tax [Abstract]
AOCI before Tax, Balance at beginning of period		139,858	(77,114)
Unrealized holding gains (losses) arising during the period		(91,511)	98,763
Less: Reclassification adjustment for net gains (losses) included in net income	[1]	10,625	(495)
Net unrealized gains (losses) on investments		(102,136)	99,258
Other comprehensive income (loss)		(102,136)	99,258
AOCI before Tax, Balance at end of period		37,722	22,144
Other Comprehensive Income, Tax [Abstract]
AOCI, Tax, Balance at beginning of period		29,370	(16,194)
Unrealized holding gains (losses) arising during the period		(19,218)	20,740
Less: Reclassification adjustment for net gains (losses) included in net income	[1]	2,231	(104)
Net unrealized gains (losses) on investments		(21,449)	20,844
Other comprehensive income (loss)		(21,449)	20,844
AOCI Tax, Balance at end of period		7,921	4,650
Other Comprehensive Income, Net of Tax [Abstract]
AOCI, Net of Tax, Balance at beginning of period		110,488	(60,920)
Unrealized holding gains (losses) arising during the period		(72,293)	78,023
Less: Reclassification adjustment for net gains (losses) included in net income (loss)	[1]	8,394	(391)
Net unrealized gains (losses) on investments		(80,687)	78,414
Other comprehensive income (loss), net of tax		(80,687)	78,414
AOCI, Net of Tax, Balance at end of period		$ 29,801	$ 17,494

[1] Included in net gains (losses) on investments and other financial instruments on our condensed consolidated statements of operations.