Income Taxes - Net Deferred Tax Assets Balance Sheet Presentation (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Non-current net deferred tax assets	$ 52,812	$ 42,434
Non-current net deferred tax liabilities	(292)	(506)
Net deferred tax assets	$ 52,520	$ 41,928