Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	$ 50,490
Other comprehensive income before reclassifications	5,333
Amounts reclassified from accumulated other comprehensive income	(651)
Other comprehensive income	4,682	705
Total accumulated other comprehensive income, ending balance	55,172
Foreign Currency [Member]
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	1,401
Other comprehensive income before reclassifications	(501)
Amounts reclassified from accumulated other comprehensive income	0
Other comprehensive income	(501)
Total accumulated other comprehensive income, ending balance	900
Unrealized holding gains on available-for-sale securities [Member]
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	49,089
Other comprehensive income before reclassifications	5,834
Amounts reclassified from accumulated other comprehensive income	(651)
Other comprehensive income	5,183
Total accumulated other comprehensive income, ending balance	$ 54,272