Nature of Operations and Basis of Presentation (Deferred Policy Acquisition Costs) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Recorded asset at beginning of period	$ 94,292
Underwriting costs deferred	158,371
Amortization of deferred policy acquisition costs	(158,440)
Recorded asset at ending of period	$ 94,223