Other Operating Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Operating Expenses [Abstract]
Amortization of gross deferred policy acquisition costs	$ 51,597	$ 50,270	$ 48,872
Other underwriting expenses	41,692	42,638	37,830
Expense allowances from reinsurers	(33,512)	(28,956)	(23,797)
Total underwriting expenses	59,777	63,952	62,905
Operating expenses of non-insurance companies	29,685	26,621	25,143
Total other operating expenses	89,462	90,573	$ 88,048
Director [Member]
Consulting Contract [Abstract]
Annual consulting contract fee	300
Expenses incurred relating to consulting contract	300	0
Commission expense	$ 419	$ 0