Effects of Reinsurance on Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Net Direct Unpaid Losses and LAE	$ 579,710	$ 441,355	$ 138,345
Net Assumed Unpaid Losses and LAE	81,493	40,877	2,510
Unpaid losses and loss adjustment expenses	661,203	482,232	140,855	$ 76,792
Net Ceded Unpaid Losses and LAE	(477,870)	(305,673)	(18,724)
Liability for Unpaid Claims and Claims Adjustment Expense, Net	183,333	176,559	122,131
Direct Unearned Premiums, Net	577,467	528,419	371,149
Assumed Unearned Premiums, Net	49,846	27,454	1,074
Unearned Premiums, Gross	627,313	555,873	372,223
Ceded Unearned Premiums, Net	(217,885)	(201,904)	(132,564)
Unearned Premiums, Net	$ 409,428	$ 353,969	$ 239,659