Investments - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) Securities	Dec. 31, 2014 Securities
Investments, Debt and Equity Securities [Abstract]
Number of securities in unrealized loss position | Securities	15	38
Proceeds from sale of investment in fixed maturity securities	$ 2.2
Investment security maturity date, start	Jan. 01, 2015
Investment security maturity date, End	Sep. 30, 2015
Gross realized gains and losses of securities	insignificant
Investments on deposit with the state insurance department	$ 4.0