Fair Value Definition and Hierarchy - Effect of Changes of Estimates on Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Change in Discount Rate | Minus 2%
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	$ 84,613	$ 91,890
Change in Discount Rate | Minus 1%
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	40,314	43,713
Change in Discount Rate | Plus 1%
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	(36,802)	(39,790)
Change in Discount Rate | Plus 2%
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	(70,497)	(76,118)
Minus 8 months | Change in Life Expectancy Estimates
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	98,909	113,812
Minus 4 months | Change in Life Expectancy Estimates
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	46,028	57,753
Plus 4 months | Change in Life Expectancy Estimates
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	(62,483)	(55,905)
Plus 8 months | Change in Life Expectancy Estimates
Summary of change in fair value of the investment in life insurance policies
Change in fair value of the investment in life insurance policies	$ (115,452)	$ (111,340)