Income Taxes - Consolidated (Loss) Income Before Taxes and Non-Controlling Interests for Domestic and Foreign Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Domestic	$ (8,386)
Foreign	(1,175)
(Loss) income before income taxes	$ (9,561)	$ 31,368	$ 73,472