Derivative Instruments (Current Period Cash Flow Hedges in AOCI (loss) before Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
AOCI Cash Flow Hedges [Roll Forward]
Balance beginning	$ (4,020)	$ 1,961	$ (4,578)	$ 403
Gains (losses) deferred in other comprehensive income (loss) on the effective portion of cash flow hedges	4,798	(6,797)	5,574	(4,934)
Amounts reclassified to investment income	(321)	(201)	(539)	(506)
Balance ending	$ 457	$ (5,037)	$ 457	$ (5,037)