Debt and Equity Securities (Change in Credit Portion of Other-Than-Temporary Impairments Recognized in Earnings on Debt Securities) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Other Than Temporary Impairment Credit Losses Recognized In Earnings [Line Items]
Cumulative credit loss on debt securities held at beginning of period	$ 16,996	$ 16,478	$ 16,478	$ 16,478
Addition to credit loss for which an other-than-temporary impairment was previously recognized	515		1,033
Cumulative credit loss on debt securities held at end of period	$ 17,511	$ 16,478	$ 17,511	$ 16,478

This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27340-111563

Name:	us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsAdditionalCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration