Accumulated Other Comprehensive Income (Rollforward of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income, Net of Tax, Beginning Balance	$ 172,262		$ 175,014
Other comprehensive income (loss)	(61,550)	$ 58,201	(64,302)	$ 101,771
Accumulated Other Comprehensive Income, Net of Tax, Ending Balance	110,712		110,712
Accumulated Net Unrealized Investment Gain [Member]
Accumulated Other Comprehensive Income, Net of Tax, Beginning Balance	174,217		169,984
Other comprehensive income (loss)	(63,472)		(59,239)
Accumulated Other Comprehensive Income, Net of Tax, Ending Balance	110,745		110,745
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income, Net of Tax, Beginning Balance	(1,955)		5,030
Other comprehensive income (loss)	1,922		(5,063)
Accumulated Other Comprehensive Income, Net of Tax, Ending Balance	$ (33)		(33)
Accumulated other comprehensive income [Member]
Other comprehensive income (loss)			$ (64,302)