Investments (Details 6) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Asset derivatives:
Derivatives Asset, Net Amount	$ 3,140	$ 2,501
Free-standing derivatives [Member]
Asset derivatives:
Derivatives Asset, Gross Amounts	3,140	2,501
Derivatives Asset, Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Derivatives Asset, Net Amounts of Assets Presented in the Consolidated Balance Sheet	3,140	2,501
Derivatives Asset, Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Derivatives Asset, Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received	2,197	2,617
Derivatives Asset, Net Amount	$ 943	$ (116)