Summary of Significant Accounting Policies - Additional Information (Detail)	Mar. 31, 2017 Country State
Accounting Policies [Abstract]
Number of countries in which company operates \| Country	20
Number of states in which company licensed to sell insurance and annuities \| State	49

The number of countries in which the entity operates as of balance sheet date.

No definition available.

Name:	us-gaap_NumberOfCountriesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant