5. Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets - Goodwill Details
Goodwill	$ 30,600	$ 30,600	$ 54,865
Measurement period adjustments	$ 0	(499)
Goodwill impairment		$ (23,766)