Accumulated Other Comprehensive Income (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
Accumulated Other Comprehensive Income, Net of Tax, Beginning Balance	$ 162,221		$ 118,651
Other comprehensive income	58,201	(141,981)	101,771	(169,152)
Accumulated Other Comprehensive Income, Net of Tax, Ending Balance	220,422		220,422
Accumulated Net Unrealized Investment Gain [Member]
Accumulated Other Comprehensive Income, Net of Tax, Beginning Balance	142,310		99,960
Other comprehensive income	57,309		99,659
Accumulated Other Comprehensive Income, Net of Tax, Ending Balance	199,619		199,619
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income, Net of Tax, Beginning Balance	19,911		18,691
Other comprehensive income	892		2,112
Accumulated Other Comprehensive Income, Net of Tax, Ending Balance	20,803		20,803
Accumulated other comprehensive income [Member]
Other comprehensive income			$ 101,771