Reserve for Losses and Loss Adjustment Expenses - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Favorable development on prior year loss reserves
Reserve for losses and loss adjustment expenses	$ (874)	$ (968)
Excess and Surplus Lines
Favorable development on prior year loss reserves
Reserve for losses and loss adjustment expenses	3	10
Specialty Admitted Insurance
Favorable development on prior year loss reserves
Reserve for losses and loss adjustment expenses	1,000	2,000
Casualty Reinsurance
Favorable development on prior year loss reserves
Reserve for losses and loss adjustment expenses	$ (1,900)	$ (3,000)