Gross and Net Realized Investment (Losses) Gains (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment gains/losses [Line Items]
OTTI	$ (174,823)	$ (58,975)	$ (6,445)
Net (losses) gains on available-for-sale securities	(42,469)	35,042	79,251
Gross gains on exchanges		31,832
Gross losses on exchanges	(11)	(11)	(84)
Net (losses) gains on held-to-maturity securities	(11)	31,821	(84)
(Provision) benefit for mortgage loans on real estate	(11,000)	(2,400)	5,000
Investment in affiliates			(6,500)
Gain on real estate sales		5,929
Investment in limited partnerships	2,150
Net gains on sales of acquired loans	2,005	24,027	95
Other		(6)
Net realized investment (losses) gains	(49,325)	94,413	77,762
Fixed-maturity securities
Investment gains/losses [Line Items]
Gross gains on sales	198,851	108,094	96,698
Gross losses on sales	(71,002)	(15,272)	(11,114)
OTTI	(172,530)	(57,598)	(6,445)
Net (losses) gains on available-for-sale securities	(44,681)	35,224	79,139
Equity securities
Investment gains/losses [Line Items]
Gross gains on sales	3,109	2	113
Gross losses on sales	(897)	(184)	(1)
Net gains (losses) on equity securities	$ 2,212	$ (182)	$ 112

Available For Sale Securities Net Realized Gains Losses

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Gain On Investments In Affiliates

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Held To Maturity Securities Gross Realized Gains

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Held To Maturity Securities Gross Realized Losses

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Investment gains/losses [Line Items]

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This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

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Amount of gain (loss) included in earnings for investments classified as other.

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The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

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The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

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This element represents the amount of loss recognized for other than temporary impairments (OTTI) of investments in debt and equity securities.

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Amount of increase (decrease) in mortgage loans on real estate.

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The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

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