Investment Securities - Summary of Net Investment Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investment income (loss):
Amortization of premium or discount on fixed-maturity securities			$ (454)	$ (1,350)
Realized net gain from sale of investments	$ 52	$ 19	319	434
Unrealized (losses) on trading securities held at period end	(38)	(283)	(311)	(651)
Net investment income	241	86	770	1,191
Cash and Cash Equivalents [Member]
Investment income (loss):
Interest income on cash and equivalents	60	2	179	9
Fixed Maturities [Member]
Investment income (loss):
Amortization of premium or discount on fixed-maturity securities	(131)	(392)	(454)	(1,350)
Investment income on fixed-maturity securities	$ 298	$ 740	$ 1,037	$ 2,749