Restructuring (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Restructuring expense	$ 0	$ (384,000)	$ 2,315,000	$ (384,000)
Restructuring liability	$ 2,526,000		$ 2,526,000		$ 2,551,000	$ 1,328,000