Property And Equipment, Net (Schedule Of Property And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross amount	$ 811,636	$ 742,592
Less accumulated depreciation and amortization	432,540	385,170
Total property and equipment, net	379,096	357,422
Land And Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross amount	7,323	7,255
Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross amount	180,185	171,455
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross amount	52,227	44,568
Machinery And Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross amount	284,375	262,718
Office Furniture And Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross amount	47,476	42,124
Computer Hardware And Software [Member]
Property, Plant and Equipment [Line Items]
Gross amount	206,580	189,327
Construction In Progress [Member]
Property, Plant and Equipment [Line Items]
Gross amount	$ 33,470	$ 25,145