Property And Equipment (Schedule Of Cost Basis And Estimated Useful Lives Of Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Building And Improvements [Member] years	Dec. 31, 2011 Computer Hardware And Software [Member] years	Dec. 31, 2011 Classroom Equipment And Other Instructional Materials [Member] years	Dec. 31, 2011 Furniture, Fixtures And Equipment [Member] years	Dec. 31, 2011 Vehicles [Member] years
Property, Plant and Equipment [Line Items]
Land	$ 3,375	$ 6,769
Building and improvements	46,769	48,087
Computer hardware and software	139,714	176,828
Classroom equipment and other instructional materials	69,350	68,306
Furniture, fixtures and equipment	98,760	109,801
Leasehold improvements	414,720	387,607
Vehicles	962	879
Construction in progress	4,764	10,955
Property and equipment, gross	778,414	809,232
Less-Accumulated depreciation	(428,626)	(445,716)
Total property and equipment, net	$ 349,788	$ 363,516
Property and equipment, minimum estimated useful life (in years)			15		5
Property and equipment, maximum estimated useful life (in years)			50		10
Property and equipment, estimated useful life (in years)				3		7	5