Property and Equipment (Components Of Property and Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 183,201	$ 173,920
Less: Accumulated depreciation	(121,546)	(116,824)
Property and equipment, net	61,655	57,096
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	92,409	88,189
Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	35,053	34,994
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	27,352	26,423
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	15,782	13,316
Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	10,846	9,239
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,759	$ 1,759
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	5 years
Minimum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	40 years
Maximum | Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	12 years
Maximum | Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	5 years
Maximum | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	40 years
Maximum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	17 years
Maximum | Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	13 years