Schedule IV - Reinsurance (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Life insurance in force, gross amount	$ 167,677,206	$ 160,455,963	$ 154,488,511
Life insurance in force, ceded to other companies	729,739	795,192	782,125
Life insurance in force, assumed from other companies	3,498,826	3,658,511	3,882,237
Life insurance in force, net amount	$ 170,446,293	$ 163,319,282	$ 157,588,623
Life insurance in force, percentage of amount assumed to net	2.10%	2.20%	2.50%
Premium, gross amount	$ 2,963,032	$ 2,796,996	$ 2,708,367
Premium, ceded to other companies	7,623	7,565	7,769
Premium, assumed from other companies	24,007	25,774	26,960
Premium income	$ 2,979,416	$ 2,815,205	$ 2,727,558
Percentage of amount assumed to net	0.80%	0.90%	1.00%
Policy charges	$ 19,300	$ 20,900	$ 22,100
Life Insurance [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Premium, gross amount	2,034,373	1,924,605	1,841,425
Premium, ceded to other companies	4,484	4,614	4,645
Premium, assumed from other companies	24,007	25,774	26,960
Premium income	$ 2,053,896	$ 1,945,765	$ 1,863,740
Percentage of amount assumed to net	1.20%	1.30%	1.40%
Health Insurance [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Premium, gross amount	$ 928,659	$ 872,391	$ 866,942
Premium, ceded to other companies	3,139	2,951	3,124
Premium, assumed from other companies	0	0	0
Premium income	$ 925,520	$ 869,440	$ 863,818
Percentage of amount assumed to net	0.00%	0.00%	0.00%

Life Insurance In Force Assumed From Other Companies

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Life Insurance In Force Ceded To Other Companies

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Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned, net of policy charges.

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Amount of earned premiums assumed from other entities.

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Amount of earned premiums ceded to other entities.

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Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

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Income from agency and brokerage operations (includes sales of annuities and supplemental contracts); service charges, commissions, and fees from the sale of insurance and related services; and management fees from separate accounts, deferred annuities, and universal life products.

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Amount before contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

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Amount after contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

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Percentage of assumed life insurance issued and outstanding contracts to life insurance issued and outstanding after contracts ceded to other entities and contracts assumed by the entity. Includes, but not limited to, dividends and adjustments to face value.

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Percentage of assumed premiums earned by the entity to net premiums earned.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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