Investments (Reclassifications of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Cash flow hedges - Currency/Interest rate
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	$ 2,981	$ 4,259
Net unrealized investments gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	2,090	4,856
Total net unrealized investment gains (losses)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	5,071	9,115	$ 16,233
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	$ 5,071	$ 9,115	$ 16,233