Note 4 - Segment Reporting Revenue and Other Segment Information (Details) - USD ($)		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
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Premiums Earned, Net		$ 301,486,000		$ 281,185,000	$ 299,166,000	$ 263,512,000	$ 261,682,000	$ 258,431,000	$ 251,344,000	$ 242,550,000	$ 1,145,349,000		$ 1,014,007,000		$ 932,773,000
Services Revenue, Net		40,031,000		42,509,000	39,303,000	32,753,000	38,414,000	36,566,000	36,828,000	33,164,000	154,596,000		144,972,000		155,103,000
Net investment income (Note 6)		41,432,000		42,756,000	43,761,000	43,847,000	42,051,000	38,995,000	37,473,000	33,956,000	171,796,000		152,475,000		127,248,000
Other income											3,495,000		4,028,000		2,886,000
Add: Net gains (losses) on investments and other financial instruments		4,257,000		$ 13,009,000	$ 12,540,000	$ 21,913,000	(11,705,000)	$ (4,480,000)	$ (7,404,000)	$ (18,887,000)	51,719,000		(42,476,000)		3,621,000
Total revenues											1,526,955,000		1,273,006,000		1,221,631,000
Interest expense											56,310,000		61,490,000		62,761,000
Depreciation											7,800,000		8,000,000.0		6,900,000
Allocation of corporate operating expenses (1)											124,412,000		94,815,000		72,764,000
Accounts Receivable, after Allowance for Credit Loss		93,630,000					78,652,000				93,630,000		78,652,000
Unbilled Contracts Receivable		13,772,000					19,917,000				13,772,000		19,917,000
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Premiums Earned, Net											1,145,349,000		1,014,007,000		932,773,000
Services Revenue, Net											158,629,000		148,217,000		161,833,000
Net investment income (Note 6)											171,796,000		152,475,000		127,248,000
Other income											3,495,000		4,028,000		2,886,000
Add: Net gains (losses) on investments and other financial instruments											0		0		0
Total revenues											1,479,269,000		1,318,727,000		1,224,740,000
Interest expense											56,310,000		61,490,000		62,761,000
Depreciation											19,001,000		18,792,000		17,073,000
Allocation of corporate operating expenses (1)											121,021,000	[1]	92,108,000	[2]	69,760,000	[3]
Operating Segments | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocation of corporate operating expenses (1)											1,800,000		600,000		300,000
Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Premiums Earned, Net											0		0		0
Services Revenue, Net											(4,033,000)		(3,245,000)		(6,730,000)
Net investment income (Note 6)											0		0		0
Other income											0		0		0
Add: Net gains (losses) on investments and other financial instruments											0		0		0
Total revenues											(4,033,000)		(3,245,000)		(6,730,000)
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Premiums Earned, Net											0		0		0
Services Revenue, Net											0		0		0
Net investment income (Note 6)											0		0		0
Other income											0		0		0
Add: Net gains (losses) on investments and other financial instruments											51,719,000		(42,476,000)		3,621,000
Total revenues											51,719,000		(42,476,000)		3,621,000
Mortgage Insurance Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Premiums Earned, Net											1,134,214,000		1,006,721,000		932,773,000
Services Revenue, Net											0		0		0
Net investment income (Note 6)											171,116,000		152,102,000		127,248,000
Other income											3,495,000		2,794,000		2,886,000
Add: Net gains (losses) on investments and other financial instruments											0		0		0
Total revenues											1,308,825,000		1,161,617,000		1,062,907,000
Interest expense											56,310,000		43,685,000		45,016,000
Depreciation											15,317,000		15,229,000		13,315,000
Allocation of corporate operating expenses (1)											104,078,000	[1]	80,134,000	[2]	55,441,000	[3]
Mortgage Insurance Segment | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocation of corporate operating expenses (1)											1,600,000		500,000		200,000
Mortgage and Real Estate Services Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Premiums Earned, Net											11,135,000		7,286,000		0
Services Revenue, Net											158,629,000		148,217,000		161,833,000
Net investment income (Note 6)											680,000		373,000		0
Other income											0		1,234,000		0
Add: Net gains (losses) on investments and other financial instruments											0		0		0
Total revenues											170,444,000		157,110,000		161,833,000
Interest expense											0		17,805,000		17,745,000
Depreciation											3,684,000		3,563,000		3,758,000
Allocation of corporate operating expenses (1)											16,943,000	[1]	11,974,000	[2]	14,319,000	[3]
Bad debt expense											0
Accounts Receivable, after Allowance for Credit Loss		10,773,000	[4]				15,461,000				10,773,000	[4]	15,461,000
Unbilled Contracts Receivable		13,772,000	[4]				19,917,000				13,772,000	[4]	19,917,000
Deferred Revenue		1,784,000	[4]				$ 3,204,000				1,784,000	[4]	3,204,000
Mortgage and Real Estate Services Segment | Held-for-sale
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Accounts Receivable, after Allowance for Credit Loss		10,500,000									10,500,000
Unbilled Contracts Receivable		$ 3,900,000									3,900,000
Mortgage and Real Estate Services Segment | Mortgage Services
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Services Revenue, Net	[5]										74,007,000		76,050,000		77,121,000
Mortgage and Real Estate Services Segment | Mortgage Services | Clayton Services LLC
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Services Revenue, Net	[5]										48,400,000		50,800,000		46,100,000
Mortgage and Real Estate Services Segment | Real Estate Services
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Services Revenue, Net											64,945,000		60,059,000		54,649,000
Mortgage and Real Estate Services Segment | Title Services
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Services Revenue, Net											15,644,000		8,863,000		23,333,000
Mortgage and Real Estate Services Segment | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocation of corporate operating expenses (1)											$ 200,000		$ 100,000		$ 100,000

[1] Includes additional depreciation expense of $1.6 million, $0.2 million and $1.8 million allocated to Mortgage Insurance, Services and Reportable Segment Total, respectively.

[2] Includes additional depreciation expense of $0.5 million, $0.1 million and $0.6 million allocated to Mortgage Insurance, Services and Reportable Segment Total, respectively.

[3] Includes additional depreciation expense of $0.2 million, $0.1 million and $0.3 million allocated to Mortgage Insurance, Services and Reportable Segment Total, respectively.

[4] Excludes $10.5 million and $3.9 million of accounts receivable and unbilled receivables, respectively, that are related to Clayton and classified as held-for-sale.

[5] Includes $48.4 million, $50.8 million and $46.1 million for the years ended December 31, 2019, 2018 and 2017, respectively, related to Clayton, which was sold in January 2020.