Nature of Operations and Basis of Presentation (Deferred Policy Acquisition Costs) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Recorded asset at beginning of period	$ 87,094
Underwriting costs deferred	54,125
Amortization of deferred policy acquisition costs	(53,264)
Recorded asset at ending of period	$ 87,955