Loss Reserves (Details) (USD $)	3 Months Ended
	Mar. 31, 2015 Loan		Mar. 31, 2014 Loan		Dec. 31, 2014 Loan
Loss Reserve [Roll Forward]
Reserve at beginning of period	$ 2,396,807,000		$ 3,061,401,000
Less reinsurance recoverable	57,841,000		64,085,000
Net reserve at beginning of period	2,338,966,000		2,997,316,000
Losses and LAE incurred in respect of default notices related to [Abstract]
Current year	109,381,000		155,982,000
Prior years	(27,596,000)	[1],[2]	(33,374,000)	[1],[2]
Subtotal	81,785,000		122,608,000
Losses and LAE paid in respect of default notices related to [Abstract]
Current year	312,000		314,000
Prior years	231,230,000		342,669,000
Subtotal	231,542,000		342,983,000
Net reserve at end of period	2,189,209,000		2,776,941,000
Plus reinsurance recoverables	55,415,000		57,618,000
Reserve at end of period	2,244,624,000		2,834,559,000
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	(27,596,000)	[1],[2]	(33,374,000)	[1],[2]
Historical average period for uncured default to develop into paid claim	12 months
Premium refund liability, expected claim payments	112,000,000				115,000,000
Primary Default Inventory [Roll Forward]
Default inventory at the beginning of period	79,901		103,328
New Notices	18,896		23,346
Cures	(21,767)		(27,318)
Paids (including those charged to a deductible or captive)	(4,573)		(7,064)
Rescissions and denials	(221)		(450)
Default inventory at end of period	72,236		91,842
Pool insurance notice inventory [Abstract]
Pool insurance notice inventory (in number of loans)	3,350		5,646
Aging of the Primary Default Inventory [Abstract]
3 months or less	11,604		14,313		15,319
3 months or less (in hundredths)	16.00%		16.00%		19.00%
4 - 11 months	18,940		23,305		19,710
4 - 11 months (in hundredths)	26.00%		25.00%		25.00%
12 months or more	41,692		54,224		44,872
12 months or more (in hundredths)	58.00%		59.00%		56.00%
Total primary default inventory	72,236		91,842
Total primary default inventory (in hundredths)	100.00%		100.00%		100.00%
Primary claims received inventory included in ending default inventory	4,448	[3]	5,990	[3]	4,746	[3]
Primary claims received inventory included in ending default inventory (in hundredths)	6.00%	[3]	7.00%	[3]	6.00%	[3]
Number of rescindable loans affected by Company's decision to voluntarily suspend rescissions	1,470		1,525		1,425
Number of payments delinquent [Abstract]
3 payments or less	19,159		23,035		23,253
3 payments or less (in hundredths)	27.00%		25.00%		29.00%
4 - 11 payments	18,372		22,766		19,427
4 - 11 payments (in hundredths)	25.00%		25.00%		24.00%
12 payments or more	34,705		46,041		37,221
12 payments or more (in hundredths)	48.00%		50.00%		47.00%
Total primary default inventory	72,236		91,842
Total primary default inventory (in hundredths)	100.00%		100.00%		100.00%
Premium refund liability, expected future rescissions	27,000,000				28,000,000
Decrease in estimated claim rate on primary defaults [Member]
Losses and LAE incurred in respect of default notices related to [Abstract]
Prior years	(39,000,000)	[1]	(30,000,000)	[1]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	(39,000,000)	[1]	(30,000,000)	[1]
Percentage of prior year default inventory resolved (in hundredths)	24.00%		25.00%
Increase in estimated severity on primary defaults [Member]
Losses and LAE incurred in respect of default notices related to [Abstract]
Prior years	17,000,000	[1]	5,000,000	[1]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	17,000,000	[1]	5,000,000	[1]
Change In Estimates Related to Pool Reserves, LAE Reserves and Reinsurance [Member]
Losses and LAE incurred in respect of default notices related to [Abstract]
Prior years	(6,000,000)	[1]	(8,000,000)	[1]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	(6,000,000)	[1]	(8,000,000)	[1]
Change in Reserve Estimates Related to Disputes on Claims Paying Practices and IBNR [Member]
Losses and LAE incurred in respect of default notices related to [Abstract]
Prior years	(20,000,000)	[1]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	$ (20,000,000)	[1]

[1] A negative number for prior year loss development indicates a redundancy of prior year loss reserves, and a positive number indicates a deficiency of prior year loss reserves.

[2] A negative number for prior year losses incurred indicates a redundancy of prior year loss reserves and a positive number for prior year losses incurred indicates a deficiency of prior year loss reserves.

[3] Our claims received inventory includes suspended rescissions, as we have voluntarily suspended rescissions of coverage related to loans that we believed would be included in a potential resolution. As of March 31, 2015, rescissions of coverage on approximately 1,470 loans had been voluntarily suspended compared to 1,425 at December 31, 2014 and 1,525 at March 31, 2014.