Reinsurance - Catastrophe Reinssurance Agreement (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
First layer participation percentage	5.00%	5.00%
First layer lower limit	$ 1,000,000	$ 1,000,000
First layer upper limit	$ 10,000,000	$ 10,000,000
Second layer participation percentage	0.00%	0.00%
Second layer lower limit	$ 10,000,000	$ 10,000,000
Second layer upper limit	$ 46,000,000	$ 46,000,000