Investments - Schedule of Investments in Fixed Maturity Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Single Maturity Date	$ 9,500
Cost	29,916	$ 18,094
Gross Unrealized Gains	156	40
Gross Unrealized Losses	(5)	(42)
Fair Value	30,067	18,092
U.S. Treasury securities, obligations of U.S. Government agencies and Municipals
Schedule of Available-for-sale Securities [Line Items]
Cost	26,787	11,876
Gross Unrealized Gains	118	6
Gross Unrealized Losses	(5)	(26)
Fair Value	26,900	11,856
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Cost		50
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		50
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Cost	3,129	4,505
Gross Unrealized Gains	38	7
Gross Unrealized Losses	0	(16)
Fair Value	$ 3,167	4,496
Short duration fixed income fund
Schedule of Available-for-sale Securities [Line Items]
Cost		1,663
Gross Unrealized Gains		27
Fair Value		$ 1,690