Quarterly Financial Results (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 243,203	$ 242,561	$ 238,096	$ 237,923	$ 267,173	$ 259,617	$ 260,459	$ 285,062	$ 961,783	$ 1,072,311	$ 1,286,633
Cost of educational services	106,852	117,539	116,276	120,115	118,432	120,204	123,541	124,176	460,782	486,353	538,350
Student services and administrative expenses	91,891	100,440	97,547	99,238	101,303	96,182	98,335	101,721	389,116	397,541	400,856
Goodwill and asset impairment	2,454								2,454	0	15,166
Legal and professional fees related to certain lawsuits, investigations and accounting matters	6,812	11,269	8,380	5,547	3,121	2,089	213	1,500	32,008	6,923	873
Loss related to loan program guarantees	0	2,019	0	0	82,335	4,826	0	3,803	2,019	90,964	101,025
Provision for private education loan losses	568	4,511	9,071	0	8,648	16,382	4,319	0	14,150	29,349	0
Operating income	34,626	6,783	6,822	13,023	(46,666)	19,934	34,051	53,862	61,254	61,181	230,363
Gain (loss) on consolidation of variable interest entities	0	16,631	0	0	0	0	0	(73,248)	16,631	(73,248)	0
Interest income	14	17	15	19	33	16	25	34	65	108	1,348
Interest (expense)	(9,305)	(5,831)	(6,263)	(6,901)	(7,144)	(7,190)	(7,369)	(3,574)	(28,300)	(25,277)	(3,723)
Income (loss) before provision for income taxes	25,335	17,600	574	6,141	(53,777)	12,760	26,707	(22,926)	49,650	(37,236)	227,988
Provision (benefit) for income taxes	10,418	7,278	182	2,519	(14,396)	3,336	6,503	(5,655)	20,397	(10,212)	89,018
Net income (loss)	$ 14,917	$ 10,322	$ 392	$ 3,622	$ (39,381)	$ 9,424	$ 20,204	$ (17,271)	$ 29,253	$ (27,024)	$ 138,970
Earnings (loss) per share:
Basic	$ 0.64	$ 0.44	$ 0.02	$ 0.15	$ (1.68)	$ 0.40	$ 0.86	$ (0.74)	$ 1.25	$ (1.15)	$ 5.82
Diluted	$ 0.63	$ 0.44	$ 0.02	$ 0.15	$ (1.68)	$ 0.40	$ 0.86	$ (0.74)	$ 1.23	$ (1.15)	$ 5.79