Reinsurance - Schedule of Ceded Premiums Earned by Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Effects of Reinsurance [Line Items]
Ceded Premiums Written	$ (42,259)	$ (35,063)
Increase (Decrease) in Ceded Unearned Premiums	(74,016)	(39,819)
Ceded Premiums Earned	(116,275)	(74,882)
Excess of Loss Product Line
Effects of Reinsurance [Line Items]
Ceded Premiums Written	(13,861)	(10,229)
Equipment and Identity Theft Product Line
Effects of Reinsurance [Line Items]
Ceded Premiums Written	(2,120)	(2,073)
Flood Product Line
Effects of Reinsurance [Line Items]
Ceded Premiums Written	(3,671)	(3,391)
Quota Share
Effects of Reinsurance [Line Items]
Ceded Premiums Written	$ (22,607)	$ (19,370)