Commitments and Contingencies - Reinsurance Agreements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Insurance Loss Reserves [Roll Forward]
Reinsurance premiums assumed	$ 0	$ 25,441
Claims assumed	0	21,151
Claims-related administrative expenses	0	4,282
Decrease in reserves for claims and performance-based arrangements attributable to the Reinsurance Agreement	0	8
Reserves for claims and performance-based arrangements attributable to the Reinsurance Agreement at the beginning of the period	0	1,243
Reinsurance payments	0	1,243
Receivables for claims and performance-based arrangements attributable to the Reinsurance Agreement at the end of the period	$ 0	$ 8