Restructuring (Restructuring Liability) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Restructuring Reserve [Roll Forward]
Balance, Beginning of the year	$ 2,551	$ 1,328
Severance and other associated costs	368	1,585
Cash payments	(2,340)	(1,328)
Wind down cost legacy platform	1,947	966
Balance, End of period	$ 2,526	$ 2,551