Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment charge	$ 3,000	$ 3,020	$ 1,733
Amount of carrying amount in excess of fair value				$ 1,700
Amortization expense		$ 500	$ 300