Reserves for Unpaid Losses and Loss Adjustment Expenses (Activity in the Reserves for Unpaid Losses and Loss Adjustment Expense) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Reserves for Unpaid Losses and Loss Adjustment Expenses [Abstract]
Balance at January 1	$ 620,355	$ 527,247
Less reinsurance recoverable	272,604	221,716
Net balance at January 1	347,751	305,531
Incurred related to:
Claims and Claim Adjustment Expenses Incurred Related to Current year	168,930	141,909
Claims and Claim Adjustment Expenses Incurred Related to Prior years	19,348	1,404
Total incurred	188,278	143,313
Paid related to:
Claims and Claim Adjustment Expenses Paid Related to Current year	38,143	38,563
Claims and Claim Adjustment Expenses Paid Related to Prior years	143,967	107,899
Total paid	182,110	146,462
Net balance at June 30	353,919	302,382
Plus reinsurance recoverable	317,017	249,161
Balance at June 30	$ 670,936	$ 551,543