Reserves for Unpaid Losses and Loss Adjustment Expenses (Activity in the Reserves for Unpaid Losses and Loss Adjustment Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reserves for Losses and Loss Adjustment Expenses
Balance at January 1	$ 527,100	$ 481,567
Less reinsurance recoverable	154,612	123,237
Net Balance at January 1	372,488	358,330
Incurred related to:
Current year	250,075	248,203
Prior years	5,953	40,105
Total incurred	256,028	288,308
Paid related to:
Current year	90,640	92,873
Prior years	232,345	181,277
Total paid	322,985	274,150
Net Balance at December 31	305,531	372,488
Plus reinsurance recoverable	221,716	154,612
Balance at December 31	$ 527,247	$ 527,100