Reserves for Unpaid Losses and Loss Adjustment Expenses (Activity in the Reserves for Unpaid Losses and Loss Adjustment Expense) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Reserves for Unpaid Losses and Loss Adjustment Expenses [Abstract]
Balance at January 1	$ 527,247	$ 527,100
Less reinsurance recoverable	221,716	154,612
Net balance at January 1	305,531	372,488
Incurred related to:
Current year	214,080	185,506
Prior years	7,781	6,062
Total incurred	221,861	191,568
Paid related to:
Current year	75,834	56,687
Prior years	146,929	184,337
Total paid	222,763	241,024
Net balance at September 30	304,629	323,032
Plus reinsurance recoverable	260,667	207,784
Balance at September 30	$ 565,296	$ 530,816