XML 43 R21.htm IDEA: XBRL DOCUMENT v3.3.0.814
Organization and Basis of Presentation (Details)
 1 Months Ended 9 Months Ended
Aug. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
state
shares
Sep. 30, 2014
USD ($)
shares
Business Acquisition [Line Items]      
Number of states in which the entity operates | state   50  
Primary insurance in force   $ 10,600,000,000  
Pool insurance in force   $ 4,300,000,000  
Antidilutive securities excluded from computation of earnings per share (in shares) | shares   6,311,956 5,854,306
Deferred policy acquisition cost, amortization expense   $ 1,800,000 $ 108,000
Premium deficiency reserve   0 $ 0
NMI Services, Inc.      
Business Acquisition [Line Items]      
Capitalized wholly owned subsidiary, amount $ 500,000    
Combined      
Business Acquisition [Line Items]      
Primary insurance risk in force   2,600,000,000  
Mortgage insurance risk in force   $ 93,100,000