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, 2017	Jun. 30, 2016
Reserves for Unpaid Losses and Loss Adjustment Expenses [Abstract]
Balance at January 1	$ 481,567	$ 450,878
Less reinsurance recoverable	123,237	102,791
Net balance at January 1	358,330	348,087
Incurred related to:
Current year	122,862	116,654
Prior years	9,684	(2,757)
Total incurred	132,546	113,897
Paid related to:
Current year	33,687	35,217
Prior years	90,042	88,377
Total paid	123,729	123,594
Net balance at June 30	367,147	338,390
Plus reinsurance recoverable	138,211	105,222
Balance at June 30	$ 505,358	$ 443,612