Schedule of Reserve for Life-Contingent Contract Benefits (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Liability for Future Policy Benefit, by Product Segment [Line Items]
Reserve for life-contingent contract benefits	$ 3,424,679	$ 3,199,490
Traditional life insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Reserve for life-contingent contract benefits	1,519,650	1,425,848
Immediate fixed annuities
Liability for Future Policy Benefit, by Product Segment [Line Items]
Reserve for life-contingent contract benefits	677,986	671,275
Accident And Health Insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Reserve for life-contingent contract benefits	1,217,648	1,092,791
Other Life Contingent Products
Liability for Future Policy Benefit, by Product Segment [Line Items]
Reserve for life-contingent contract benefits	$ 9,395	$ 9,576

The sum of the known and estimated amounts payable as of the balance sheet date to policyholders pertaining to insured events for long-duration contracts, which can be viewed as either (a) the present value of future benefits to be paid to or on behalf of policyholders and expenses less the present value of future net premiums payable under the insurance contracts or (b) the accumulated amount of net premiums already collected less the accumulated amount of benefits and expenses already paid to or on behalf of policyholders.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 21-26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 97

-Paragraph 15-21

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 40

-Section 25

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=6482067&loc=d3e13145-158430

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 113

-Paragraph 26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph a

-Article 7

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.13(a)(1))

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

+ Details