Goodwill and Other Intangible Assets (Other Intangible Assets) (Details) 2 (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012 year	Dec. 31, 2011 year
Amortized intangible assets [Abstract]
Gross Carrying Amount	$ 128,047	$ 146,934
Accumulated Amortization	81,253	92,312
Net Carrying Amount	46,794	54,622
Indefinite Lived Intangible Assets Excluding Goodwill [Line Items]
Indefinite-Lived Intangible Assets, Net	525,833	530,641
Franchise Agreements [Member]
Indefinite Lived Intangible Assets Excluding Goodwill [Line Items]
Indefinite-Lived Intangible Assets, Net	496,321	496,321
Wireless Licenses [Member]
Indefinite Lived Intangible Assets Excluding Goodwill [Line Items]
Indefinite-Lived Intangible Assets, Net	22,150	22,150
Licensure and Accreditation [Member]
Indefinite Lived Intangible Assets Excluding Goodwill [Line Items]
Indefinite-Lived Intangible Assets, Net	7,362	7,862
Other [Member]
Indefinite Lived Intangible Assets Excluding Goodwill [Line Items]
Indefinite-Lived Intangible Assets, Net	0	4,308
Non-compete Agreements [Member]
Amortized intangible assets [Abstract]
Useful Life, minimum (in years)	2	2
Useful Life, maximum (in years)	5	5
Gross Carrying Amount	14,348	14,493
Accumulated Amortization	12,215	10,764
Net Carrying Amount	2,133	3,729
Student and Customer Relationships [Member]
Amortized intangible assets [Abstract]
Useful Life, minimum (in years)	2	2
Useful Life, maximum (in years)	10	10
Gross Carrying Amount	65,185	75,734
Accumulated Amortization	38,944	47,888
Net Carrying Amount	26,241	27,846
Databases and Technology [Member]
Amortized intangible assets [Abstract]
Useful Life, minimum (in years)	3	3
Useful Life, maximum (in years)	5	5
Gross Carrying Amount	6,457	10,514
Accumulated Amortization	5,332	8,159
Net Carrying Amount	1,125	2,355
Trade Names and Trademarks [Member]
Amortized intangible assets [Abstract]
Useful Life, minimum (in years)	2	2
Useful Life, maximum (in years)	10	10
Gross Carrying Amount	32,713	36,222
Accumulated Amortization	18,225	18,936
Net Carrying Amount	14,488	17,286
Other [Member]
Amortized intangible assets [Abstract]
Useful Life, minimum (in years)	1	1
Useful Life, maximum (in years)	25	25
Gross Carrying Amount	9,344	9,971
Accumulated Amortization	6,537	6,565
Net Carrying Amount	$ 2,807	$ 3,406