Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	$ 3,346	$ 4,236
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	3,332	4,245	1,954
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Other expense (income), net	(165)	11,472	(410)
Income tax expense	29,840	35,175	33,259
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0	88
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	(14)	9
Other Comprehensive Income Loss Reclassification Adjustments Total Net of Tax	(14)	97
Accumulated Translation Adjustment [Member]
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Other expense (income), net	0	116
Income tax expense	0	(28)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock [Line Items]
Other expense (income), net	(23)	14
Income tax expense	$ 9	$ (5)