Reserves for Unpaid Losses and Loss Adjustment Expenses (Activity in the Reserves for Unpaid Losses and Loss Adjustment Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 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	84,846	70,153
Claims and Claim Adjustment Expenses Incurred Related to Prior years	8,559	(66)
Total incurred	93,405	70,087
Paid related to:
Claims and Claim Adjustment Expenses Paid Related to Current year	14,525	12,633
Claims and Claim Adjustment Expenses Paid Related to Prior years	80,888	60,581
Total paid	95,413	73,214
Net balance at March 31	345,743	302,404
Plus reinsurance recoverable	307,747	227,822
Balance at March 31	$ 653,490	$ 530,226