Reinsurance - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Maximum amount of mortality risk retained	$ 1,000
Reinsurance receivables - net	$ 1,987	$ 2,186
GMIB
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Percentage of account value for variable annuity contracts reinsured	37.00%	39.00%
GMDB
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Percentage of account value for variable annuity contracts reinsured	6.00%	6.00%

Amount after valuation allowance recoverable including premium paid under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 6

-Article 7

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 20

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6824-158387

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a),6)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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