Summary of Significant Accounting Policies - Deferred Offering Costs and Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Oct. 04, 2016
Deferred Offering Costs
Deferred offering costs		$ 2,298	$ 3,960
Goodwill
Goodwill impairment	$ 0	$ 0