Change In Net Unrealized Gains And Losses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Gross unrealized gains (losses)					$ 46,982		$ 24,611
Deferred income tax	7,906		(322)		15,702		8,251
Change in unrealized gains (losses) on investments, net of tax	14,727	[1]	(511)	[1]	31,280	[2]	16,360	[2]
Fixed maturities
Gross unrealized gains (losses)					38,165		32,898
Equity Securities
Gross unrealized gains (losses)					$ 8,817		$ (8,287)

[1] Disclosure of reclassification amount, net of tax: Unrealized gains (losses) on investments arising during period $ 16,866 $ 411 Reclassification adjustment for net realized gains (losses) included in net income (2,139 ) (1,025 ) Reclassification adjustment for other-than-temporary impairment losses recognized in net income - 103 Change in net unrealized gains (losses) on investments, net of tax $ 14,727 $ (511 )

[2] Disclosure of reclassification amount, net of tax: Unrealized gains (losses) on investments arising during period $ 33,456 $ 15,986 Reclassification adjustment for net realized gains (losses) included in net income (2,513 ) 264 Reclassification adjustment for other-than-temporary impairment losses recognized in net income 337 110 Change in net unrealized gains (losses) on investments, net of tax $ 31,280 $ 16,360