Equity Method Investments - Summarized unaudited financial data (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Summary financial information of equity method investments
Current assets	$ 7,234
Non-current assets	56,783
Current liabilities	35,109
Non-current liabilities	52,514
Redeemable stock and noncontrolling interests	14,235
Net revenue	4,396
Operating loss	(17,473)
Net loss	$ (19,788)