Reinsurance - Excess of Loss 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	$ 500,000	$ 500,000
First layer upper limit	$ 1,000,000	$ 1,000,000
Second layer participation percentage	0.00%	0.00%
Second layer lower limit	$ 1,000,000	$ 1,000,000
Second layer upper limit	$ 3,000,000	$ 4,000,000
Clash participation	0.00%	0.00%
Renaissance Reinsurance U.S., Inc.
A.M. Best Rating	A+	A
Combined Retention (All Reinsurers)	$ 500,000	$ 500,000
Hannover Ruck SE
A.M. Best Rating	A+	A+
Combined Retention (All Reinsurers)	$ 500,000	$ 500,000