Change In Net Unrealized Gains And Losses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Gross unrealized gains (losses)					$ 24,349		$ 25,444
Deferred income tax	2,976		8,390		7,796		8,573
Change in unrealized gains (losses) on investments, net of tax	7,604	[1]	16,833	[1]	16,553	[2]	16,871	[2]
Fixed maturities
Gross unrealized gains (losses)					17,439		21,206
Equity Securities
Gross unrealized gains (losses)					$ 6,910		$ 4,238

[1] Disclosure of reclassification amount, net of tax: Unrealized gains (losses) on investments arising during period $ 9,039 $ 15,450 Reclassification adjustment for net realized gains (losses) included in net income (1,607 ) 1,326 Reclassification adjustment for other-than-temporary impairment losses recognized in net income 172 57 Change in net unrealized gains (losses) on investments, net of tax $ 7,604 $ 16,833

[2] Disclosure of reclassification amount, net of tax: Unrealized gains (losses) on investments arising during period $ 17,643 $ 16,011 Reclassification adjustment for net realized gains (losses) included in net income (1,335 ) 830 Reclassification adjustment for other-than-temporary impairment losses recognized in net income 245 30 Change in net unrealized gains (losses) on investments, net of tax $ 16,553 $ 16,871