Property And Equipment (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Property, Plant and Equipment [Line Items]
Depreciation expense for continuing operations	$ 77,500,000	$ 68,800,000	$ 63,500,000
Depreciation expense for discontinued operations	900,000	1,600,000	3,200,000
Gain on sale of property	1,711,000	(457,000)	(1,291,000)
Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges		300,000	2,500,000
Leased Facilities [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges		300,000
Owned Facilities [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges			2,500,000
California [Member]
Property, Plant and Equipment [Line Items]
Gain on sale of property	$ 1,400,000