Investments - Fair Value and Gross Unrealized Losses of Fixed Maturity Securities in Continuous Unrealized Loss Position for Greater than 12 Months (Detail)	Sep. 30, 2016 USD ($) Security	Dec. 31, 2015 USD ($) Security
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | Security	0	4
Fair Value	$ 0	$ 7,689,000
Gross Unrealized Losses	$ 0	$ (241,000)
Percentage of amortized cost less than or equal to 10%
Schedule of Available-for-sale Securities [Line Items]
Number of Securities | Security		4
Fair Value		$ 7,689,000
Gross Unrealized Losses		$ (241,000)