Regulatory Information (Tables)
 6 Months Ended
Jun. 30, 2018
Insurance [Abstract]  
Schedule of Statutory Net Loss, Surplus, Contingency Reserve and Risk-to-Capital Ratio
NMIC and Re One's combined statutory net income (loss) was as follows:
 
For the three months ended June 30,
 
For the six months ended June 30,
 
2018
 
2017
 
2018
 
2017
 
(In Thousands)
Statutory net income (loss)
$
2,066

 
$
(11,616
)
 
$
(4,748
)
 
$
(21,706
)
NMIC and Re One's statutory surplus, contingency reserve and risk-to-capital (RTC) ratios were as follows:
 
June 30, 2018
 
December 31, 2017
 
(Dollars In Thousands)
Statutory surplus
$
439,754

 
$
371,084

Contingency reserve
253,817

 
186,641

RTC Ratio
13.7:1

 
13.2:1