Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidated Statements Of Income [Abstract]
Revenue	$ 341,794	$ 383,171
Costs and expenses:
Cost of educational services	134,941	137,926
Student services and administrative expenses	106,266	104,583
Total costs and expenses	241,207	242,509
Operating income	100,587	140,662
Interest income	681	835
Interest (expense)	(547)	(557)
Income before provision for income taxes	100,721	140,940
Provision for income taxes	39,650	55,554
Net income	$ 61,071	$ 85,386
Earnings per share:
Basic	$ 2.40	$ 2.94
Diluted	$ 2.38	$ 2.91
Weighted average shares outstanding:
Basic	25,420	29,085
Diluted	25,636	29,312