Investments (Other Long Term Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Other Long Term Investments [Line Items]
Total other long-term investments	$ 379,237	$ 298,143
Company’s investment in separate accounts
Other Long Term Investments [Line Items]
Total other long-term investments	28,567	25,761
Joint ventures and limited partnerships
Other Long Term Investments [Line Items]
Total other long-term investments	280,570	244,330
Derivatives
Other Long Term Investments [Line Items]
Total other long-term investments	$ 70,100	$ 28,052