Nature of Business and Basis of Presentation (Details) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Jun. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Nature of Business and Basis of Presentation [Abstract]
PMIERs effective days after publication			180 days
Mortgage Insurers transition period			2 years
Period for submission of transition plan to GSE			90 days
Holding company cash and investments			$ 517,000,000
Assets of regulated insurance affiliates of MGIC			100,000,000
(Increase) decrease in restricted cash	42,900,000	(60,300,000)	(233,000)	60,348,000
Restricted cash and cash equivalents	$ 17,440,000		$ 17,207,000