Supplementary Insurance Information, for Insurance Companies Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	$ 0	$ 0	$ 0
Selling, General and Administrative Expenses
Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Costs	$ 340	$ 319	$ 3,524