Restructuring and Exit Costs (Schedule of Restructuring and Exit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended			15 Months Ended	18 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016	Sep. 30, 2016
Restructuring Reserve [Roll Forward]
Costs incurred	$ 1,300	$ 1,000	$ 2,282	$ 297	$ 2,512
Consolidation of US Manufacturing Operations
Restructuring Reserve [Roll Forward]
Restructuring liability		802	802	1,337	0
Costs incurred			179	451	2,647	$ 3,000
Restructuring cash payments				(453)	(1,010)		$ (1,500)
Accruals released				(154)	(135)
Lease payments and accretion			(311)	(379)	(165)
Restructuring liability			670	802	1,337
Consolidation of US Manufacturing Operations | Employee Severance Costs
Restructuring Reserve [Roll Forward]
Restructuring liability		0	0	294	0
Costs incurred			0	67	1,439	1,200
Restructuring cash payments				(207)	(1,010)
Accruals released				(154)	(135)
Lease payments and accretion			0	0	0
Restructuring liability			0	0	294
Consolidation of US Manufacturing Operations | Lease Obligation Costs
Restructuring Reserve [Roll Forward]
Restructuring liability		802	802	1,043	0
Costs incurred			179	86	1,208	1,500
Restructuring cash payments				0	0
Accruals released				0	0
Lease payments and accretion			(311)	(327)	(165)
Restructuring liability			670	802	1,043
Consolidation of US Manufacturing Operations | Other Exit Costs
Restructuring Reserve [Roll Forward]
Restructuring liability		$ 0	0	0	0
Costs incurred			0	298	0	$ 300
Restructuring cash payments				(246)	0
Accruals released				0	0
Lease payments and accretion			0	(52)	0
Restructuring liability			$ 0	$ 0	$ 0