Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	$ 52,230
Other comprehensive income before reclassifications	(157)
Amounts reclassified from accumulated other comprehensive income	514
Other comprehensive income	357	4,682
Total accumulated other comprehensive income, ending balance	52,587
Foreign Currency [Member]
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	390
Other comprehensive income before reclassifications	(779)
Amounts reclassified from accumulated other comprehensive income	0
Other comprehensive income	(779)
Total accumulated other comprehensive income, ending balance	(389)
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	51,840
Other comprehensive income before reclassifications	622
Amounts reclassified from accumulated other comprehensive income	514
Other comprehensive income	1,136
Total accumulated other comprehensive income, ending balance	$ 52,976