Restatement and Revision of Previously Issued Unaudited Financial Statements - Effect of Revisions on Affected Line Items on Condensed Consolidated Statement of Income (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Condensed Consolidated Statement of Income Data:
Revenue	$ 260,459	$ 328,061	$ 545,521		$ 667,270
Cost of educational services	123,541	140,067	247,717		275,008
Student services and administrative expenses	98,335	105,895	200,056		207,214
Legal and other investigation costs	213	873	1,713		873
Loss related to loan program guarantees	0	3,906	3,803		6,960
Total costs and expenses	226,408	250,741	457,608		490,055
Income (loss) before provision for income taxes	26,707	76,568	3,781		176,597
Provision for income taxes	6,503	30,627	849		70,011
Net income	20,204	45,941	2,932	32,384	106,586
Earnings per share:
Basic	$ 0.86	$ 1.96	$ 0.13		$ 4.37
Diluted	$ 0.86	$ 1.95	$ 0.12		$ 4.34
As Previously Reported [Member]
Condensed Consolidated Statement of Income Data:
Revenue	259,936	329,825	547,647		671,619
Cost of educational services	123,828	140,940	249,049		275,881
Student services and administrative expenses	100,903	111,467	207,185		217,733
Legal and other investigation costs	0	0	0		0
Loss related to loan program guarantees		0	3,464		0
Total costs and expenses	224,731	252,407	459,698		493,614
Income (loss) before provision for income taxes	34,264	76,666	85,890		177,387
Provision for income taxes	13,405	30,664	33,901		70,314
Net income	20,859	46,002	51,989		107,073
Earnings per share:
Basic	$ 0.89	$ 1.97	$ 2.22		$ 4.39
Diluted	$ 0.89	$ 1.96	$ 2.21		$ 4.36
Revisions [Member]
Condensed Consolidated Statement of Income Data:
Revenue		(1,764)			(4,349)
Cost of educational services		0			0
Student services and administrative expenses		(5,572)			(10,519)
Legal and other investigation costs		0			0
Loss related to loan program guarantees		3,906			6,960
Total costs and expenses		(1,666)			(3,559)
Income (loss) before provision for income taxes		(98)			(790)
Provision for income taxes		(37)			(303)
Net income		(61)			(487)
Reclassifications [Member]
Condensed Consolidated Statement of Income Data:
Revenue	0	0	0		0
Cost of educational services	(287)	(873)	(1,332)		(873)
Student services and administrative expenses	74	0	(381)		0
Legal and other investigation costs	213	873	1,713		873
Loss related to loan program guarantees		0	0		0
Total costs and expenses	0	0	0		0
Income (loss) before provision for income taxes	0	0	0		0
Provision for income taxes	0	0	0		0
Net income	$ 0	$ 0	$ 0		$ 0