Schedule II. Condensed Financial Information of Registrant - Condensed Balance Sheets (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Condensed Balance Sheet Statements, Captions [Line Items]
Net of Treasury stock	$ 22,370us-gaap_TreasuryStockValue	$ 22,370us-gaap_TreasuryStockValue
Parent Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Net of Treasury stock	$ 22,370	$ 22,370

The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23315-112656

Name:	us-gaap_TreasuryStockValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant