Reinsurance Recoverables (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Reinsurance Recoverable [Line Items]
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	$ 434,196	$ 477,870	$ 399,814	$ 305,673
Reinsurance Recoverable for Paid Claims and Claims Adjustments	220,264	148,128
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments	$ 654,460	$ 625,998