Variable Interest Entities - Schedule of Revenue and Expenses of PEAKS Trust (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Variable Interest Entity [Line Items]
Student services and administrative expenses	$ 100,440	$ 96,182	$ 297,225	$ 296,238
Provision for PEAKS Trust student loan losses	4,511us-gaap_ProvisionForLoanAndLeaseLosses	16,382us-gaap_ProvisionForLoanAndLeaseLosses	13,582us-gaap_ProvisionForLoanAndLeaseLosses	20,701us-gaap_ProvisionForLoanAndLeaseLosses
Interest expense	5,831us-gaap_InterestExpense	7,190us-gaap_InterestExpense	18,995us-gaap_InterestExpense	18,133us-gaap_InterestExpense
Income before provision for income taxes	17,600	12,760	24,315	16,541
PEAKS Trust [Member]
Variable Interest Entity [Line Items]
Revenue	2,727	4,072	9,099	9,536
Student services and administrative expenses	987	1,535	3,624	3,613
Provision for PEAKS Trust student loan losses	4,511	16,382	13,582	20,701
Interest expense	5,261	6,275	16,875	14,953
Income before provision for income taxes	$ (8,032)	$ (20,120)	$ (24,982)	$ (29,731)

Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Amount of expense related to estimated loss from loan and lease transactions.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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