Investments - Major Categories of Investment Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Investment Income [Line Items]
Investment income	$ 1,268	$ 1,762	$ 2,544	$ 3,532
Investment expenses	(169)	(162)	(336)	(318)
Fixed Maturities, Available-for-Sale [Member]
Net Investment Income [Line Items]
Investment income	1,270	1,746	2,553	3,506
Mutual Fund, Available-for-Sale [Member]
Net Investment Income [Line Items]
Investment income	145	140	285	277
Other [Member]
Net Investment Income [Line Items]
Investment income	$ 22	$ 38	$ 42	$ 67