Investments (Reclassifications of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flow hedges - Currency/Interest rate
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	$ (827)	$ 1,801
Net unrealized investments gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	(14,097)	313
Total net unrealized investment gains (losses)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	(14,924)	2,114
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	$ (14,924)	$ 2,114