Life Settlements (Life Insurance Policies) - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) Contract	Dec. 31, 2014 USD ($) Contract
Investments, All Other Investments [Abstract]
Number of policies owned (contracts) | Contract	634	607
Life insurance estimated fair value	$ 457,810	$ 388,886
Average life expectancy of insured	10 years
Estimated future premium payments	$ 1,434,524