Severance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Charges	$ 1,446	$ 2,701	$ 1,495
Severance costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve	1,356	1,581
Charges	1,446	2,701
Cash Paid	(1,347)	(2,926)
Restructuring Reserve	$ 1,455	1,356	$ 1,581
Former Executive | Severance costs
Restructuring Reserve [Roll Forward]
Charges		$ 1,800