Investments - Components of Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Strategic investments:
Investments accounted for under the equity method	$ 87,099	$ 86,853
Investments held at fair value	2,093	1,814
Investments held at adjusted cost	2,293	8,746
Total strategic investments	91,485	97,413
Other investments	2,290	1,530
Total investments	$ 93,775	$ 98,943