Schedule V - Supplemental Information Concerning Property and Casualty Insurance Operations (Parenthetical) (Detail)	Dec. 31, 2015	Dec. 31, 2014
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Discount deducted from claim and claim adjustment expense reserves interest rates, Minimum	3.50%	3.50%
Discount deducted from claim and claim adjustment expense reserves interest rates, Maximum	8.00%	8.00%

The maximum interest rate in the range of rates estimated at which the discount was computed for each business segment reported.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-18)
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e575016-122915

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant