Restructuring and Exit Costs (Schedule of Restructuring and Exit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Reserve [Roll Forward]
Costs incurred	$ 1,251	$ 0	$ 2,248	$ 297
February 2017 Restructuring Plan
Restructuring Reserve [Roll Forward]
Costs incurred	100		900
February 2017 Restructuring Plan | Employee Severance Costs
Restructuring Reserve [Roll Forward]
Restructuring liability as of December 31, 2016			0
Costs incurred			997
Amounts paid			(855)
Accruals released			(142)
Restructuring liability as of September 30, 2017	0		0
September 2017 Restructuring Plan
Restructuring Reserve [Roll Forward]
Costs incurred			1,200
September 2017 Restructuring Plan | Employee Severance Costs
Restructuring Reserve [Roll Forward]
Restructuring liability as of December 31, 2016			0
Costs incurred			1,195
Amounts paid			(58)
Accruals released			0
Restructuring liability as of September 30, 2017	$ 1,137		$ 1,137