Goodwill and Other Intangible Assets (Other Intangible Assets) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	176,276	182,107
Accumulated Amortization	85,422	85,160
Net Carrying Amount	90,854	96,947
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Net	510,966	516,753
Franchise Agreements [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Net	496,321	496,321
Licensure and Accreditation [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Net	994	6,781
Other [Member]
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Net	13,651	13,651
Non-compete Agreements [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	1,680	2,500
Accumulated Amortization	1,070	1,590
Net Carrying Amount	610	910
Non-compete Agreements [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	2 years	2 years
Non-compete Agreements [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	5 years	5 years
Student and Customer Relationships [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	103,480	104,685
Accumulated Amortization	49,503	47,539
Net Carrying Amount	53,977	57,146
Student and Customer Relationships [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	2 years	2 years
Student and Customer Relationships [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	10 years	10 years
Databases and Technology [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	10,518	10,501
Accumulated Amortization	9,024	8,827
Net Carrying Amount	1,494	1,674
Databases and Technology [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	3 years	3 years
Databases and Technology [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	5 years	5 years
Trade Names and Trademarks [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	54,281	55,452
Accumulated Amortization	20,812	19,724
Net Carrying Amount	33,469	35,728
Trade Names and Trademarks [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	2 years	2 years
Trade Names and Trademarks [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	10 years	10 years
Other [Member]
Amortized Intangible Assets [Line Items]
Gross Carrying Amount	6,317	8,969
Accumulated Amortization	5,013	7,480
Net Carrying Amount	1,304	1,489
Other [Member] | Minimum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	1 year	1 year
Other [Member] | Maximum [Member]
Amortized Intangible Assets [Line Items]
Useful Life	25 years	25 years