Restatement of Previously Issued Unaudited Financial Statements - Summary of Table Sets Forth the Effect of Consolidation and Correction of Errors and Reclassifications of 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
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Revenue	$ 260,459	$ 328,061	$ 545,521		$ 667,270
Costs and expenses:
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
Provision for PEAKS Trust student loan losses	4,319	0	4,319		0
Total costs and expenses	226,408	250,741	457,608		490,055
Operating income (loss)	34,051	77,320	87,913		177,215
(Loss) on consolidation of PEAKS Trust	0	0	(73,248)		0
Interest income	25	502	59		1,183
Interest (expense)	(7,369)	(1,254)	(10,943)		(1,801)
Income (loss) before provision for income taxes	26,707	76,568	3,781		176,597
Provision (benefit) for income taxes	6,503	30,627	849		70,011
Net income (loss)	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
Weighted average shares outstanding:
Basic	23,414	23,390	23,406		24,405
Diluted	23,550	23,529	23,516		24,583
As Previously Reported [Member]
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Revenue	259,936	329,825	547,647		671,619
Costs and expenses:
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
Provision for PEAKS Trust student loan losses	0		0
Total costs and expenses	224,731	252,407	459,698		493,614
Operating income (loss)	35,205		87,949
(Loss) on consolidation of PEAKS Trust	0		0
Interest income	172		206
Interest (expense)	(1,113)		(2,265)
Income (loss) before provision for income taxes	34,264	76,666	85,890		177,387
Provision (benefit) for income taxes	13,405	30,664	33,901		70,314
Net income (loss)	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
Weighted average shares outstanding:
Basic	23,414		23,406
Diluted	23,550		23,516
Consolidation of PEAKS Trust [Member]
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Revenue	4,104		5,464
Costs and expenses:
Cost of educational services	0		0
Student services and administrative expenses	1,559		2,078
Legal and other investigation costs	0		0
Loss related to loan program guarantees			0
Provision for PEAKS Trust student loan losses	4,319		4,319
Total costs and expenses	5,878		6,397
Operating income (loss)	(1,774)		(933)
(Loss) on consolidation of PEAKS Trust	0		(73,248)
Interest income	(147)		(147)
Interest (expense)	(6,256)		(8,678)
Income (loss) before provision for income taxes	(8,177)		(83,006)
Provision (benefit) for income taxes	(7,141)		(33,399)
Net income (loss)	(1,036)	(61)	(49,607)		(487)
Other Adjustments [Member]
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Revenue	(3,581)		(7,590)
Costs and expenses:
Cost of educational services	0		0
Student services and administrative expenses	(4,201)		(8,826)
Legal and other investigation costs	0		0
Loss related to loan program guarantees			339
Provision for PEAKS Trust student loan losses	0		0
Total costs and expenses	(4,201)		(8,487)
Operating income (loss)	620		897
(Loss) on consolidation of PEAKS Trust	0		0
Interest income	0		0
Interest (expense)	0		0
Income (loss) before provision for income taxes	620		897
Provision (benefit) for income taxes	239		347
Net income (loss)	381	45,941	550		106,586
Reclassifications [Member]
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Revenue	0	0	0		0
Costs and expenses:
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
Provision for PEAKS Trust student loan losses	0		0
Total costs and expenses	0	0	0		0
Operating income (loss)	0		0
(Loss) on consolidation of PEAKS Trust	0		0
Interest income	0		0
Interest (expense)	0		0
Income (loss) before provision for income taxes	0	0	0		0
Provision (benefit) for income taxes	0	0	0		0
Net income (loss)	$ 0	$ 0	$ 0		$ 0