Restructuring Charges (Schedule Of Accrued Restructuring Balances) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 1,283	$ 1,336
Restructuring charges	4,936	4,693
Cash Payment	(5,891)	(4,728)
Non-Cash Activity	(42)	(21)
Foreign Exchange Adjustments	4	3
Ending Balance	290	1,283	$ 1,336
2017 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Restructuring charges	2,967
Cash Payment	(2,724)
Non-Cash Activity	0
Foreign Exchange Adjustments	2
Ending Balance	245	0
2016 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,283	0
Restructuring charges	1,969	4,607
Cash Payment	(3,167)	(3,303)
Non-Cash Activity	(42)	(21)
Foreign Exchange Adjustments	2	0
Ending Balance	45	1,283	0
2015 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	1,336
Restructuring charges		86	8,305
Cash Payment		(1,425)
Non-Cash Activity		0
Foreign Exchange Adjustments		3
Ending Balance		0	1,336
Severance [Member] | 2017 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Restructuring charges	2,172
Cash Payment	(2,125)
Non-Cash Activity	0
Foreign Exchange Adjustments	0
Ending Balance	47	0
Severance [Member] | 2016 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	738	0
Restructuring charges		3,630
Restructuring Reserve Accrual Adjustment	(42)
Cash Payment	(667)	(2,892)
Non-Cash Activity	0	0
Foreign Exchange Adjustments	0	0
Ending Balance	29	738	0
Severance [Member] | 2015 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	222
Restructuring Reserve Accrual Adjustment		(1)
Cash Payment		(224)
Non-Cash Activity		0
Foreign Exchange Adjustments		3
Ending Balance		0	222
Lease Facility Costs [Member] | 2017 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Restructuring charges	264
Cash Payment	(264)
Non-Cash Activity	0
Foreign Exchange Adjustments	0
Ending Balance	0	0
Lease Facility Costs [Member] | 2016 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	0
Restructuring charges	58	0
Cash Payment	(58)	0
Non-Cash Activity	0	0
Foreign Exchange Adjustments	0	0
Ending Balance	0	0	0
Lease Facility Costs [Member] | 2015 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0	928
Restructuring charges		109
Cash Payment		(1,037)
Non-Cash Activity		0
Foreign Exchange Adjustments		0
Ending Balance		0	928
Other Exit Costs [Member] | 2017 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0
Restructuring charges	531
Cash Payment	(335)
Non-Cash Activity	0
Foreign Exchange Adjustments	2
Ending Balance	198	0
Other Exit Costs [Member] | 2016 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	545	0
Restructuring charges	1,953	977
Cash Payment	(2,442)	(411)
Non-Cash Activity	(42)	(21)
Foreign Exchange Adjustments	2	0
Ending Balance	16	545	0
Other Exit Costs [Member] | 2015 [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 0	186
Restructuring Reserve Accrual Adjustment		(22)
Cash Payment		(164)
Non-Cash Activity		0
Foreign Exchange Adjustments		0
Ending Balance		$ 0	$ 186