Note 4 - Segment Reporting Reconciliation of Segment to Consolidated Results Pretax (Details) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017 USD ($) customer	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) customer	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) customer	Dec. 31, 2016 USD ($) customer	Dec. 31, 2015 USD ($) customer
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net gains (losses) on investments and other financial instruments										$ 3,621		$ 35,693
Net gains on investments and other financial instruments		$ (1,339)	$ 2,480	$ 5,331	$ (2,851)	$ (38,773)	$ 7,711	$ 30,527	$ 31,286	3,621	$ 30,751	35,693
Loss on induced conversion and debt extinguishment (Note 12)		0	(45,766)	(1,247)	(4,456)	0	(17,397)	(2,108)	(55,570)	(51,469)	(75,075)	(94,207)
Business Combination, Acquisition Related Costs	[1]									(105)	(519)	(1,565)
Goodwill, Impairment Loss		0	0	(184,374)	0					(184,374)	0	0
Increase (Decrease) in Goodwill and Intangible Assets		$ (2,629)	$ (2,890)	(18,856)	$ (3,296)	$ (3,290)	$ (3,292)	$ (3,311)	$ (3,328)	(27,671)	(13,221)	(12,986)
Impairment of Long-Lived Assets Held-for-use	[2]									(10,440)	0	0
Pretax Income (Loss) from Continuing Operations Attributable to Parent										346,737	483,686	437,829
Mortgage Insurance Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss) Pre-Tax Non-GAAP	[3]									$ 651,015	$ 561,911	$ 511,048
Mortgage Insurance Segment | Primary Risk In Force [Member] | CALIFORNIA | Geographic Concentration Risk [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Concentration Risk, Percentage										12.40%
Mortgage Insurance Segment | Primary Risk In Force [Member] | Minimum [Member] | CALIFORNIA | Geographic Concentration Risk [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Concentration Risk, Percentage										10.00%
Mortgage Insurance Segment | New Insurance Written [Member] | Customer A [Member] | Customer Concentration Risk [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Concentration Risk, Percentage										6.80%	5.70%	4.60%
Mortgage Insurance Segment | New Insurance Written [Member] | CALIFORNIA | Geographic Concentration Risk [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Concentration Risk, Percentage										14.10%	14.80%	15.20%
Mortgage Insurance Segment | Earned Premium Benchmark, Amount [Member] | Customer B [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Entity Wide Revenue, Major Customer, Number of Customers | customer		1				1				1	1	1
Mortgage Insurance Segment | Earned Premium Benchmark, Amount [Member] | Customer B [Member] | Customer Concentration Risk [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Concentration Risk, Percentage										15.00%	15.00%	16.00%
Mortgage and Real Estate Services Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss) Pre-Tax Non-GAAP	[3]									$ (33,840)	$ (20,161)	$ (154)
Goodwill, Impairment Loss				$ (184,400)						(184,374)	0
Mortgage Insurance and Mortgage and Real Estate Services Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss) Pre-Tax Non-GAAP										$ 617,175	$ 541,750	$ 510,894

[1] Acquisition-related expenses represent expenses incurred to effect the acquisition of a business, net of adjustments to accruals previously recorded for acquisition expenses.

[2] Included within restructuring and other exit costs. See Note 2.

[3] Includes inter-segment expenses and revenues as listed in the notes to the preceding tables.