Loss Reserves - Default Inventory Reconciliation (Details) - loan	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Primary Default Inventory [Roll Forward]
Default inventory at beginning of year	62,633	79,901	103,328
New Notices	67,434	74,315	88,844
Cures	(65,516)	(73,610)	(87,278)
Paids (including those charged to a deductible or captive)	(12,367)	(16,004)	(23,494)
Rescissions and denials	(629)	(848)	(1,306)
Other items removed from inventory	(1,273)	(1,121)	(193)
Default inventory at end of year	50,282	62,633	79,901