Investments - Major Categories of Investment Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Investment Income [Line Items]
Investment income	$ 1,473	$ 1,624	$ 4,017	$ 5,156
Investment expenses	(117)	(159)	(453)	(477)
Fixed Maturities, Available-for-Sale [Member]
Net Investment Income [Line Items]
Investment income	1,262	1,629	3,815	5,136
Mutual Fund, Available-for-Sale [Member]
Net Investment Income [Line Items]
Investment income	176	144	462	420
Limited Partnership Interests [Member]
Net Investment Income [Line Items]
Investment income	128		128
Other [Member]
Net Investment Income [Line Items]
Investment income	$ 24	$ 10	$ 65	$ 77