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, 2017	Mar. 31, 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	62,331	57,112
Prior years	(489)	(1,717)
Total incurred	61,842	55,395
Paid related to:
Current year	12,583	11,819
Prior years	47,533	48,128
Total paid	60,116	59,947
Net balance at March 31	360,056	343,535
Plus reinsurance recoverable	126,915	105,594
Balance at March 31	$ 486,971	$ 449,129