Change In Net Unrealized Gains And Losses (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Gross unrealized gains (losses)	$ 9,720	$ 44,529	$ (4,808)
Deferred income tax	3,418	15,143	(1,324)
Change in net unrealized gains (losses), net	6,302	29,386	(3,484)
Fixed maturities
Gross unrealized gains (losses)	15,709	44,712	(12,039)
Equity Securities
Gross unrealized gains (losses)	$ (5,989)	$ (183)	$ 7,231