Variable Interest Entities - Schedule of Carrying Value of Assets and Liabilities of PEAKS Trust (Detail) - USD ($) $ in Thousands	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Variable Interest Entity [Line Items]
Restricted cash	$ 6,328	$ 6,040	$ 4,293
Current portion of PEAKS Trust student loans	9,541	10,584	7,713
PEAKS Trust student loans, excluding current portion, less allowance for loan losses of $39,596, $42,353 and $29,349	76,528	80,292	75,619
Total assets	740,258	752,838	780,332
Current portion of PEAKS Trust senior debt	26,533	37,545	130,692
Other current liabilities	28,602	27,153	52,268
PEAKS Trust senior debt, excluding current portion	45,127	48,166	63,693
Total liabilities	592,335	610,766	664,089
PEAKS Trust [Member]
Variable Interest Entity [Line Items]
Restricted cash	1,727	1,556	1,640
Current portion of PEAKS Trust student loans	6,475	7,169	7,713
PEAKS Trust student loans, excluding current portion, less allowance for loan losses of $39,596, $42,353 and $29,349	57,596	59,902	75,619
Total assets	65,798	68,627	84,972
Current portion of PEAKS Trust senior debt	26,533	37,545	130,692
Other current liabilities	175	199	449
PEAKS Trust senior debt, excluding current portion	45,127	48,166	63,693
Total liabilities	$ 71,835	$ 85,910	$ 194,834

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.18)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Aggregate carrying amount of current liabilities (due within one year or within the normal operating cycle if longer) not separately disclosed in the balance sheet. Includes costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered and of liabilities not separately disclosed.

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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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