Policy Benefits for Life and Annuity Contracts - Schedule of Life and Annuity Benefits (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Insurance [Abstract]
Life	$ 436,603	$ 344,215
Annuities	921,654	938,121
Policy benefits for life and annuity contracts	1,358,257	1,282,336
Fair value adjustments	(53,560)	(61,472)
Policy benefits for life and annuity contracts, net of fair value adjustments	$ 1,304,697	$ 1,220,864

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

Name:	us-gaap_LiabilityForFuturePolicyBenefitsIndividualAndGroupAnnuitiesAndSupplementaryContracts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant