Restructuring (Restructuring Liability) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Balance, Beginning of the year	$ 2,338	$ 2,551
Severance and other associated costs	2,084	648
Cash payments	(1,845)	(2,807)
Wind down cost legacy platform	0	1,946
Balance, End of period	$ 2,577	$ 2,338