Accumulated Other Comprehensive Income Roll Forward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) Roll Forward [Line Items]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	$ 4,632		$ 1,811
Unrealized gain on available-for-sale investments, net of tax (benefit)	2,829
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(1,841)
Other Comprehensive Income Loss Arising During Period Total Net of Tax	988
Foreign currency translation adjustment, net of tax (benefit)	(1,753)	1,463
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance	(88)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance	980
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	(8)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax	88
Other Comprehensive Income Loss Reclassification Adjustments Total Net of Tax	80
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	2,821	127
Other Comprehensive Income (Loss), Net of Tax	1,068	1,590
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	$ (3,652)		$ (1,899)