Restructuring (Changes in Restructuring Accruals) (Details) - Realignment of Office Furniture Facilities and Exit of Business Line $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2016	$ 2,704
Restructuring charges, excluding accelerated depreciation	3,325
Cash payments	(4,060)
Balance as of September 30, 2017	1,969
Severance
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2016	2,704
Restructuring charges, excluding accelerated depreciation	841
Cash payments	(2,711)
Balance as of September 30, 2017	834
Facility Exit Costs & Other
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2016	0
Restructuring charges, excluding accelerated depreciation	2,484
Cash payments	(1,349)
Balance as of September 30, 2017	$ 1,135