Realized Gains And Losses Excluding Net Other-Than-Temporary Impairment Losses Recognized in Earnings (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
Gain (Loss) on Investments [Line Items]
Net realized gains (losses)	$ 4,217	$ 3,006	$ 6,059	$ 1,618
Fixed maturities
Gain (Loss) on Investments [Line Items]
Gains	4,717	4,443	7,858	7,312
Losses	(231)	(2,277)	(1,530)	(6,534)
Net realized gains (losses)	4,486	2,166	6,328	778
Equity Securities
Gain (Loss) on Investments [Line Items]
Gains	204	840	204	840
Losses	(473)		(473)
Net realized gains (losses)	$ (269)	$ 840	$ (269)	$ 840

The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.3(a))

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 325

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6485959&loc=d3e22529-158502

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 3

-Subparagraph a

-Article 7

Name:	us-gaap_RealizedInvestmentGainsLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration