Policy Benefits for Life and Annuity Contracts - Schedule of Life and Annuity Benefits (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Life	$ 433,358	$ 436,603
Annuities	917,594	921,654
Policy benefits for life and annuity contracts	1,350,952	1,358,257
Fair value adjustments	(51,829)	(53,560)
Policy benefits for life and annuity contracts, net of fair value adjustments	$ 1,299,123	$ 1,304,697

Amount of accrued obligation to policyholders that relates to insured events under individual and group annuities and supplementary insurance contracts.

Reference 1: 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=28366191&loc=d3e13145-158430

Reference 2: 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant