Variable Interest Entities - Schedule of Carrying Value of Assets and Liabilities of PEAKS Trust (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Feb. 28, 2013
Variable Interest Entity [Line Items]
Restricted cash	$ 5,974	$ 5,636	$ 4,989
Current portion of PEAKS Trust student loans	10,339	7,730	7,598
PEAKS Trust student loans, excluding current portion	84,272	76,479	85,340
Total assets	767,506us-gaap_Assets	806,851us-gaap_Assets	739,302us-gaap_Assets
Current portion of PEAKS Trust senior debt	96,516us-gaap_LongTermDebtCurrent	157,883us-gaap_LongTermDebtCurrent	134,075us-gaap_LongTermDebtCurrent
Other current liabilities	27,838us-gaap_OtherLiabilitiesCurrent	42,136us-gaap_OtherLiabilitiesCurrent	57,485us-gaap_OtherLiabilitiesCurrent
PEAKS Trust senior debt, excluding current portion	44,000us-gaap_LongTermDebtNoncurrent	71,341us-gaap_LongTermDebtNoncurrent	94,420us-gaap_LongTermDebtNoncurrent
Total liabilities	635,971us-gaap_Liabilities	691,205us-gaap_Liabilities	598,067us-gaap_Liabilities
PEAKS Trust [Member]
Variable Interest Entity [Line Items]
Restricted cash	1,450	2,593	1,237	1,703
Current portion of PEAKS Trust student loans	6,933	7,730	7,598	7,282
PEAKS Trust student loans, excluding current portion	60,479	76,479	85,340	104,834
Total assets	68,862	86,802	94,175	113,819
Current portion of PEAKS Trust senior debt	96,516	157,883	134,075	103,356
Other current liabilities	287	697	496	471
PEAKS Trust senior debt, excluding current portion	44,000	71,341	94,420	122,740
Total liabilities	$ 140,803	$ 229,921	$ 228,991	$ 226,567

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

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An amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money within one year from the balance sheet date (or the normal operating cycle, whichever is longer), net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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