Commitments and Contingencies - Reinsurance Agreements (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Insurance Loss Reserves [Roll Forward]
Claims reserves attributable to the Reinsurance Agreement at the beginning of the year	$ 0
Reinsurance premiums assumed	3,242
Claims assumed	3,934
Claims-related administrative expenses	551
(Increase) decrease in claims reserves attributable to the Reinsurance Agreement	(1,243)
Claims reserves attributable to the Reinsurance Agreement at the end of the year	$ 1,243