Nature of Business and Basis of Presentation (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013
Nature of Business and Basis of Presentation [Abstract]
Shortfall in available assets under PMIERs	$ 230,000,000
Assets of regulated insurance affiliates of MGIC	45,000,000
Holding company cash and investments	494,000,000
PMIERs tables expected review period	2 years
Notice period for updates to PMIERs tables	180 days
(Increase) decrease in restricted cash	$ 17,212,000	$ (4,000)	$ 42,900,000	$ (60,300,000)