Fair Value Measurement - Cash and Cash Equivalents Reconciliation (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Cash Equivalents, at Carrying Value [Abstract]
Cash equivalents	$ 12,041	$ 62,024	$ 50,006
Cash	138,184	190,812	171,779
Total cash and cash equivalents	$ 150,225	$ 252,836	$ 221,785	$ 255,961