Note 3 - Segment Reporting Reconciliation of Segment to Consolidated Results Pretax (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)		$ 164,103	$ 125,281
Net gains (losses) on investments and other financial instruments		(18,887)	(2,851)
Loss on induced conversion and debt extinguishment		0	(4,456)
Acquisition-related (expenses) benefits	[1]	0	(8)
Increase (Decrease) in Goodwill and Intangible Assets		(2,748)	(3,296)
Impairment of Long-Lived Assets Held-for-use	[2]	(26)	0
Pretax income		142,442	114,670
Mortgage Insurance Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	[3]	171,711	134,633
Mortgage and Real Estate Services Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	[3]	(7,608)	$ (9,352)
Goodwill, Impairment Loss		$ 0		$ (184,374)

[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 1.

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