Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 162,283	$ 94,760
Tuition receivable, net	16,942us-gaap_AccountsReceivableNetCurrent	15,842us-gaap_AccountsReceivableNetCurrent
Other current assets	17,426us-gaap_OtherAssetsCurrent	16,738us-gaap_OtherAssetsCurrent
Total current assets	196,651us-gaap_AssetsCurrent	127,340us-gaap_AssetsCurrent
Property and equipment, net	82,266us-gaap_PropertyPlantAndEquipmentNet	94,421us-gaap_PropertyPlantAndEquipmentNet
Deferred income taxes	16,241us-gaap_DeferredTaxAssetsNetNoncurrent	17,129us-gaap_DeferredTaxAssetsNetNoncurrent
Goodwill	6,800us-gaap_Goodwill	6,800us-gaap_Goodwill
Other assets	5,857us-gaap_OtherAssetsNoncurrent	8,576us-gaap_OtherAssetsNoncurrent
Total assets	307,815us-gaap_Assets	254,266us-gaap_Assets
Current liabilities:
Accounts payable and accrued expenses	43,836	38,527
Income taxes payable	1,286us-gaap_TaxesPayableCurrent	2,569us-gaap_TaxesPayableCurrent
Deferred revenue	4,682us-gaap_DeferredRevenueCurrent	656us-gaap_DeferredRevenueCurrent
Other current liabilities	281us-gaap_OtherLiabilitiesCurrent	281us-gaap_OtherLiabilitiesCurrent
Current portion of term loan	6,250us-gaap_LongTermDebtCurrent	3,125us-gaap_LongTermDebtCurrent
Total current liabilities	56,335us-gaap_LiabilitiesCurrent	45,158us-gaap_LiabilitiesCurrent
Term loan, less current portion	112,500us-gaap_LongTermDebtNoncurrent	118,750us-gaap_LongTermDebtNoncurrent
Other long-term liabilities	46,248	51,456
Total liabilities	215,083us-gaap_Liabilities	215,364us-gaap_Liabilities
Commitments and contingencies
Stockholders' equity:
Common stock, par value $0.01; 20,000,000 shares authorized; 10,797,464 and 10,903,341 shares issued and outstanding at December 31, 2013 and 2014, respectively	109us-gaap_CommonStockValue	108us-gaap_CommonStockValue
Additional paid-in capital	14,550	7,137
Retained earnings	77,985	31,629
Accumulated other comprehensive income	88	28
Total stockholders' equity	92,732us-gaap_StockholdersEquity	38,902us-gaap_StockholdersEquity
Total liabilities and stockholders' equity	$ 307,815	$ 254,266

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant