Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance	$ 8,082	$ 8,021	$ 8,123
Additions related to current year tax positions	193	61	519
Reductions for prior year tax positions	(2,257)		(621)
Balance	$ 6,018	$ 8,082	$ 8,021