Summary of Significant Accounting Policies - Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($) Investment Insured	Dec. 31, 2018 Insured
Accounting Policies [Abstract]
Prepaid management fee amortization period	7 years
Charges for extended reporting coverage | $	$ 0
Age for extended reporting coverage for policyholders	55 years
Minimum duration of policy for extended coverage	1 year
Number of investment accounted for greater than 5% | Investment	0
Number of insured accounted for over 20% | Insured	0	0