Fair Value - Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Liabilities:
Participating preferred shares derivative liability	$ 76,860	$ 69,810	$ 63,240	$ 62,790
Recurring
Liabilities:
Participating preferred shares derivative liability	76,860	69,810
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Participating preferred shares derivative liability	0	0
Recurring \| Significant Other Observable Inputs (Level 2)
Liabilities:
Participating preferred shares derivative liability	0	0
Recurring \| Significant Unobservable Inputs (Level 3)
Liabilities:
Participating preferred shares derivative liability	$ 76,860	$ 69,810