Accounting Policies - VIE Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Current assets	$ 76,863	$ 51,354
Non-current assets	24,757	25,607
Current liabilities	48,065	29,324
Non-current liabilities	$ 31,496	$ 28,849