Document and Entity Information [Abstract] Document And Entity Information [Abstract] Statement [Table] Statement [Line Items] Document Type Amendment Flag Document Period End Date Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Filer Category Entity Common Stock, Shares Outstanding Condensed Consolidated Balance Sheets [Abstract] Assets, Abstract Assets Cash and cash equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period ShortTermInvestments Short-term investments Short-term investments Short-term investments Restricted cash Accounts receivable, less allowance for doubtful accounts of $7,526 and $25,227 Accounts receivable, less allowance for doubtful accounts of $7,526 and $25,227 Accounts receivable, net Accounts receivable, net Deferred Tax Assets, Net, Current Deferred Tax Assets, Net, Current, Ending Balance Deferred Tax Assets, Net, Current, Beginning Balance Deferred income taxes Deferred Tax Assets, Net, Current, Total Prepaid expenses and other current assets Prepaid expenses and other current assets Total current assets Total current assets Property and equipment, net Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Property and equipment, net Deferred Tax Assets, Net, Noncurrent Deferred income taxes Deferred Tax Assets, Net, Noncurrent, Total Other assets Other assets Assets Total assets Liabilities and Shareholders' Equity Accounts Payable, Current Accounts payable Accounts Payable, Current, Total Accrued compensation and benefits Employee-related Liabilities, Current, Total Other Liabilities, Current Other current liabilities Other Liabilities, Current, Total Deferred revenue Deferred revenue Total current liabilities Total current liabilities Long-term debt Other liabilities Other liabilities Liabilities Total liabilities Shareholders' equity: Preferred stock, $.01 par value, 5,000,000 shares authorized, none issued Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued, Beginning Balance Preferred Stock, Value, Issued, Total Common stock, $.01 par value, 300,000,000 shares authorized, 37,068,904 issued at December 31, 2010 and 54,068,904 issued at December 31, 2009 Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common Stock, Value, Issued, Total Common stock, $.01 par value, 300,000,000 shares authorized, 37,068,904 issued Additional Paid in Capital, Common Stock Additional Paid in Capital, Common Stock, Ending Balance Additional Paid in Capital, Common Stock, Beginning Balance Capital surplus Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained earnings Retained earnings Accumulated other comprehensive (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated other comprehensive (loss) Treasury stock, 17,123,838, 15,352,376 and 15,376,719 shares, at cost Treasury stock, 12,934,377, 10,969,425 and 8,999,196 shares, at cost Treasury Stock, Value, Ending Balance Treasury Stock, Value, Beginning Balance Total shareholders' equity Balance, value Balance, value Balance Total shareholders' equity Total liabilities and shareholders' equity Total liabilities and shareholders' equity Preferred stock - Par value Preferred stock, par value Preferred stock - Authorized Preferred stock, authorized Preferred stock - Issued Preferred Stock, Shares Issued, Total Preferred stock, issued Common stock - Par value Common stock, par value Common stock - Authorized Common stock, authorized Common stock - Issued Number of common stock issued Common Stock, Shares, Issued, Total Common stock, issued Treasury stock - Shares Treasury Stock, Shares, Ending Balance Treasury Stock, Shares, Beginning Balance Shares of common stock held in treasury Treasury stock, shares Condensed Consolidated Statements Of Income [Abstract] Sales Revenue, Net Revenue Sales Revenue, Net, Total Costs and expenses: Costs associated with the normal operations of providing educational services to students. Cost Of Educational Services Cost of educational services Selling, General and Administrative Expense Student services and administrative expenses Selling, General and Administrative Expense, Total Costs and Expenses Total costs and expenses Total costs and expenses Operating income Operating income Operating income Investment Income, Net Interest income Interest income Interest Expense Interest (expense) Interest (expense) Interest (expense) Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Income before provision for income taxes Income before provision for income taxes Provision for income taxes Provision for income taxes Provision for income taxes Total provision for income taxes Provision for income taxes Net income Net Income (Loss) Attributable to Parent, Total Net Income Net income Net income Earnings Per Common Share [Abstract] Earnings per share: Earninings Per Share, Basic Basic Basic Earnings per share: Basic Earnings Per Share, Diluted Diluted Diluted Earnings per share: Diluted Weighted average shares outstanding: Basic Weighted average number of shares of common stock outstanding Weighted Average Number of Shares Outstanding, Basic, Total Diluted Outstanding shares for diluted earnings per share calculation Weighted Average Number of Shares Outstanding, Diluted, Total Condensed Consolidated Statements Of Comprehensive Income [Abstract] Other comprehensive income: Other comprehensive income, net of tax: Other Comprehensive Income Amortization Of Defined Benefit Plan Net Prior Service Cost Recognized In Net Periodic Pension Cost Net Of Tax Prior service cost amortization, net of income tax of $151 and $135 Prior service cost amortization, net of income tax of $151 and $135 Prior service costs, net of income tax The adjustment out of other comprehensive income for actuarial gains or losses recognized as a component of net periodic benefit cost during the period, after tax. Other Comprehensive Income Loss Reclassification Pension And Other Postretirement Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Net actuarial pension loss amortization, net of income tax of $272 and $186 Net actuarial pension loss, net of income tax Unrealized gain (loss) Unrealized (losses) Unrealized (loss) Available-for-sale Securities, Gross Unrealized Losses, Total Unrealized (losses) on available-for-sale securities, net of income tax of $0 and $0 Other Comprehensive Income (Loss), Net of Tax Other comprehensive income (loss), net of tax Comprehensive income Comprehensive income Amortization of prior service cost, income tax Prior service cost, income tax Prior service cost, income tax Amortization of prior service cost, income tax Prior service costs, income tax For each annual statement of income presented, the tax effect of the net gain (loss) recognized in other comprehensive income that is a reclassification adjustment of other comprehensive income as a result of being recognized as a component of net periodic benefit cost for the period. Other Comprehensive Income Loss Reclassification Pension And Other Postretirement Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Tax Net actuarial pension loss, income tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Unrealized (losses) on available-for-sale securities, income tax Condensed Consolidated Statements Of Cash Flows [Abstract] Cash flows from operating activities: Adjustments to reconcile net income to net cash flows from operating activities: Adjustments to reconcile net income to net cash flows from operating activities: Depreciation and amortization Depreciation and amortization Depreciation and amortization expense Provision for doubtful accounts Deferred income taxes Total deferred income tax expense (benefit) Excess Tax Benefit from Share-based Compensation, Operating Activities Excess tax benefit from stock option exercises Excess tax benefit from stock option exercises Share-based Compensation Stock-based compensation expense Share-based Compensation, Total Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities, Total Other Changes in operating assets and liabilities: Changes in operating assets and liabilities: Changes in operating assets and liabilities: Increase (Decrease) in Restricted Cash for Operating Activities Restricted cash Restricted cash Accounts receivable Accounts receivable Accounts payable Accounts payable Cash equivalents Other operating assets and liabilities Other operating assets and liabilities Other operating assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net, Total Increase (Decrease) In Deferred Revenue Deferred revenue Net Cash Provided by (Used in) Operating Activities Net cash flows from operating activities Cash flows from investing activities: Cash flows from investing activities: The cash outflow for purchases of and improvement on land and buildings Facility And Land Expenditures Facility expenditures and land purchases Facility expenditures and land purchases Payments to Acquire Other Productive Assets Capital expenditures, net Capital expenditures, net Proceeds from sales and maturities of investments and repayment of notes Proceeds from sales and maturities of investments and repayment of notes Proceeds from sales and maturities of investments Purchase of investments Purchase of investments and note advances Purchase of investments Net Cash Provided by (Used in) Investing Activities Net cash flows from investing activities Cash flows from financing activities: Excess tax benefit from stock option exercises Proceeds from exercise of stock options Payments of Debt Issuance Costs Debt issue costs Debt issue costs Proceeds from Long-term Lines of Credit Proceeds from revolving borrowings Repayments of Long-term Lines of Credit Repayment of revolving borrowings Repayment of revolving borrowings Payments for Repurchase of Common Stock Repurchase of common stock and shares tendered for taxes Repurchase of common stock and shares tendered for taxes Net Cash Provided by (Used in) Financing Activities Net cash flows from financing activities Net change in cash and cash equivalents Net change in cash and cash equivalents Condensed Consolidated Statements Of Shareholders' Equity [Abstract] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Parent [Member] Parent [Member] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Capital Surplus [Member] Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income/Loss [Member] Treasury Stock [Member] Common Stock In Treasury [Member] Shares, Issued Balance, shares Balance, shares Amortization of net actuarial pension loss Net actuarial pension loss amortization, net of income tax of $272 and $186 Net actuarial pension loss, net of income tax Other Comprehensive Income, Defined Benefit Plan's Net Unamortized (Gain) Loss Arising During Period, Net of Tax Pension settlement loss, net of income tax Net actuarial pension loss, net of income tax Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, Net of Tax Pension settlement loss, net of $470 of income tax Pension settlement loss, net of income tax Stock Issued During Period Value Share Based Compensation Exercise of stock options and equity awards, value Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures, Total Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures, Total Exercise of stock options and equity awards, shares Tax benefit from exercise of stock options and restricted stock vesting Tax benefit from exercise of stock options and equity award vesting Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Total Common shares repurchased, value Common shares repurchased, value Total cost Common shares repurchased, shares Common shares repurchased, shares Outstanding shares of common stock repurchased Number of shares Value of shares issued during the period to Directors for compensation Stock Issued During Period Value Director Compensation Issuance of shares for Directors' compensation, value Number of shares issued during the period to Directors for compensation Stock Issued During Period Shares Director Compensation Issuance of shares for Directors' compensation, shares Shares Tendered For Taxes, Value of shares Shares tendered for taxes, value Shares tendered for taxes, value Shares Tendered For Taxes, number of shares Shares tendered for taxes, shares Shares tendered for taxes, shares Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax Net actuarial pension loss, income tax Net actuarial pension loss amortization, income tax Net actuarial pension loss, income tax Net actuarial pension loss, income tax Net actuarial pension loss, income tax Net actuarial pension loss amortization, income tax Net actuarial pension loss, income tax Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, Tax Pension settlement loss, income tax The Company And Basis Of Presentation [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] The Company And Basis Of Presentation Business and Significant Accounting Policies New Accounting Guidance [Abstract] Description of New Accounting Pronouncements Not yet Adopted [Text Block] New Accounting Guidance Fair Value [Abstract] Fair Value Disclosures Text Block Fair Value Equity Compensation [Abstract] Disclosure Of Compensation Related Costs Share Based Payments Text Block Equity Compensation Stock Repurchases [Abstract] Stock Repurchases [Abstract] Treasury Stock [Text Block] Stock Repurchases Debt [Abstract] Debt [Abstract] Debt Disclosure [Text Block] Debt Investments [Abstract] Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure Text Block Investments n/a Variable Interests [Abstract] Variable Interests [Text Block] Variable Interests Earnings Per Share Earnings Per Common Share Employee Pension Benefits [Abstract] Pension And Other Postretirement Benefits Disclosure Text Block Employee Pension Benefits Employee Pension Benefits Contingencies [Abstract] Commitments And Contingencies Disclosure Text Block Contingencies Commitments and Contingencies Fair Value, by Balance Sheet Grouping [Text Block] Fair Value Measurement Of Financial Assets Schedule Of Stock Based Compensation Expense And Related Income Tax Benefit Recognized In Condensed Consolidated Statements Of Income Table Text Block Schedule Of Stock-Based Compensation Expense And Related Income Tax Benefit Recognized In Condensed Consolidated Statements Of Income Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Stock Options Granted and Exercised Schedule Of Stock Options Granted, Forfeited, Exercised And Expired Tabular disclosure of stock options granted and exercised during the period. Schedule Of Stock Options Granted And Exercised Table [Text Block] Schedule Of Stock Options Granted And Exercised Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Fair Value Of Stock Option Grant Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] Number Of Restricted Stock Units Granted, Forfeited And Vested Schedule Of Treasury Stock By Class Text Block Schedule Of Common Stock Repurchased Schedule of Interest Expense [Table Text Block] Schedule of Interest Expense [Table Text Block] Interest Expense Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Available-For-Sale Investments Unrealized Gain (Loss) on Investments [Table Text Block] Unrealized Gains And Losses On Available-For-Sale Investments Schedule Of Components Of Investment Income Included In Interest Income [Table Text Block] Schedule Of Components Of Investment Income Included In Interest Income [Table Text Block] Components Of Investment Income Schedule Of Weighted Average Number Of Shares [Table Text Block] Schedule Of Historical Net Income And The Weighted Average Number Of Shares Of Common Stock Outstanding Schedule of Net Benefit Costs [Table Text Block] Schedule Of Components Of Net Periodic Pension Benefit Of The ESI Pension Plan And ESI Excess Pension Plan Number of students enrolled in master, bachelor and associate degree programs Number Of Students In Degree Programs Number of students in degree programs Number of states where online programs are offered. Number Of States For Online Programs Number of states where online programs are offered Total number of campuses and learning sites in operation. Number Of Locations In Operation Number of locations Number of campuses in operation. Number Of Campuses Number of campuses Number of learning sites in operation. Number Of Learning Sites Number of learning sites Number of States in which Entity Operates Number of states Financial Instruments, Owned, at Fair Value Financial Instruments, Owned, at Fair Value, Total Estimated fair value of financial instruments Long Term Debt Fair Value Estimated fair value of long-term debt Disclosure of the carrying value of the Notes Receivable at the reporting date. Notes Receivable Carrying Value Disclosure Carrying value of financial instruments Disclosure of the carrying value of the long-term portion of the Line of Credit at the reporting date. Line of Credit Carrying Value Disclosure Carrying value of long-term debt Fair Value, by Balance Sheet Grouping [Table] Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis] Fair Value Plan Asset Measurement [Domain] Fair Value Plan Asset Measurement [Domain] Fair Value Inputs Level1 [Member] (Level 1) Quoted Prices In Active Markets For Identical Assets [Member] Fair Value Inputs Level2 [Member] (Level 2) Significant Other Observable Inputs [Member] Fair Value Inputs Level3 [Member] (Level 3) Significant Unobservable Inputs [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and Cash Equivalents, Fair Value Disclosure Cash equivalents Available-for-sale Securities, Fair Value Disclosure Short-term investments Aggregate Fair Value Other Assets, Fair Value Disclosure Other assets Assets, Fair Value Disclosure Financial assets fair value disclosure Assets, Fair Value Disclosure, Total Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost Capitalization of stock-based compensation cost Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Pre-tax compensation expense for unvested stock-based compensation grants Service Period Applicable To Grantees On Weighted Average Basis Service period applicable to the grantees on a weighted-average basis, years Number of restricted stock units vested during the period that were settled in cash. Share Based Compensation Arrangement Restricted Stock Units Settled In Cash Number of RSUs vested in the period that were settled in cash The total fair value of restricted stock units for which the grantee gained the right during the period, by satisfying service requirements, to receive cash in accordance with the terms of the arrangement. Share Based Compensation Arrangement Restricted Stock Units Settled In Cash Vested In Period Fair Market Value RSUs vested and settled in cash, amount Number of restricted stock units vested during the period that were settled in shares of common stock Share Based Compensation Arrangement Restricted Stock Units Settled In Shares Of Common Stock Number of RSUs vested in the period that were settled in shares of common stock The total fair value of restricted stock units for which the grantee gained the right during the period, by satisfying service requirements, to receive common shares in accordance with the terms of the arrangement. Share Based Compensation Arrangement Restricted Stock Units Settled In Shares Vested In Period Fair Market Value RSUs vested and settled in shares of common stock, amount Allocated Share-based Compensation Expense Stock-based compensation expense Allocated Share-based Compensation Expense, Total Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Income tax (benefit) Income tax (benefit) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Number of Shares, Outstanding at end of period Number of Shares, Outstanding at beginning of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period Issuance of shares for Directors' compensation, shares Shares subject to stock options granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures, Total Number of Shares, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Number of Shares, Forfeited Stock Issued During Period Shares Stock Options Exercised Number of Shares, Exercised Shares subject to stock options exercised Stock Issued During Period Shares Stock Options Exercised Number of Shares, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Number of Shares, Expired Number of Shares, Expired Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Number of Shares, Exercisable at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted Average Exercise Price, Outstanding at end of period Weighted Average Exercise Price, Outstanding at beginning of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Exercised Weighted Average Exercise Price, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Expired Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted Average Exercise Price, Exercisable at end of period The aggregate exercise price at which grantees can acquire the shares reserved for issuance under the stock option plan. Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Aggregate Exercise Price Aggregate Exercise Price, Outstanding at end of period Aggregate Exercise Price, Outstanding at beginning of period The total price at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period. Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Aggregate Exercise Price Aggregate Exercise Price, Granted The total price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period. Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Aggregate Exercise Price Aggregate Exercise Price, Forfeited The total price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period. Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Aggregate Exercise Price Aggregate Exercise Price, Exercised Aggregate Exercise Price, Exercised The total price at which all grantees could have acquired the underlying shares with respect to stock options of the plan that lapsed during the reporting period. Share Based Compensation Arrangement By Share Based Payment Award Options Expirations In Period Aggregate Exercise Price Aggregate Exercise Price, Expired Aggregate Exercise Price, Expired The total price at which all grantees with stock options could acquire shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Aggregate Exercise Price Aggregate Exercise Price, Exercisable at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted Average Remaining Contractual Term, Outstanding at end of period, years Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term, Beginning of Period Weighted Average Remaining Contractual Term for shares outstanding at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Weighted Average Remaining Contractual Term, Exercisable at end of period, years Weighted Average Remaining Contractual Term for shares exercisable at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate Intrinsic Value, Outstanding at end of period Aggregate Intrinsic Value for shares outstanding at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Aggregate Intrinsic Value, Exercisable at end of period Aggregate Intrinsic Value for shares outstanding at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted average grant date fair value per share Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value Intrinsic value of stock options exercised Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Proceeds received from stock options exercised Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options, Total Tax Benefit From Stock Options Exercised Excess tax benefit from stock option exercises Tax benefits realized from stock options exercised Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Risk-free interest rates Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected lives (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number # of RSUs, Unvested at end of period # of RSUs, Unvested at beginning of period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period # of RSUs, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period # of RSUs, Forfeited Number of RSUs, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period # of RSUs, Vested Number of RSUs, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Unvested at end of period Weighted Average Grant Date Fair Value, Unvested at beginning of period Unvested at beginning of period Unvested at end of period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Vested Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased Shares remaining available for repurchase Treasury Stock Acquired, Average Cost Per Share Average cost per share Repurchase authorization average cost per share Line of Credit Facility [Table] Debt Instrument [Axis] Debt Instrument Name [Domain] Debt Instrument, Name [Domain] New Credit Agreement [Member] New Credit Agreement [Member] New Credit Agreement [Member] Prior Credit Agreement [Member] Prior Credit Agreement [Member] Prior Credit Agreement [Member] Line of Credit Facility [Axis] Line Of Credit Facility Lender [Domain] Line of Credit Facility, Lender [Domain] Revolving Credit Facility, One [Member] Revolving Credit Facility One [Member] Revolving Credit Facility, One [Member] Revolving Credit Facility, Two [Member] Revolving Credit Facility Two [Member] Revolving Credit Facility, Two [Member] Line of Credit Facility [Line Items] Line of Credit Facility, Maximum Borrowing Capacity Maximum borrowing capacity The amount of additional commitments that may be obtained under the credit agreement if approved by the lenders. Line Of Credit Additional Possible Lending Commitments Additional revolving commitments or term loan commitments under the New Credit Agreement Number of line of credit facilities. Line Of Credit Facilities Number Number of credit facilities under the Prior Credit Agreement Line of Credit Facility, Expiration Date Revolving credit facility, maturity date Percentage per annum paid on the daily amount of the commitment by the lenders under the lines of credit, whether used or unused. Line Of Credit Facility Fee Percentage Percentage of daily amount of commitment paid as facility fee under the Prior Credit Agreement Secured Long-term Debt, Noncurrent Borrowings under the New Credit Agreement Line Of Credit Facility, Interest Rate At Period End Interest rate under the New Credit Agreement Line of Credit Facility, Interest Rate During Period Effective interest rate on borrowings Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Commitment fee under the New Credit Agreement Interest Expense, Debt Interest expense Interest Expense, Debt, Total Certificates of Deposit, at Carrying Value Certificate of deposit, total principal value Available-for-sale Securities, Debt Maturities, within One Year, Fair Value Debt securities classified as available-for-sale Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities, Major Types of Debt and Equity Securities [Axis] Major Types Of Debt And Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Government Obligations [Member] Government Obligations [Member] Government Obligations [Member] Government Agency Obligations [member] Government Agency Obligations [Member] Government Agency Obligations [Member] Corporate Bond Securities [Member] Corporate Obligations [Member] Schedule of Available-for-sale Securities [Line Items] Available-for-sale Securities, Debt Maturities, Amortized Cost Amortized Cost Available-for-sale Securities, Debt Maturities, Amortized Cost, Total Available-for-sale Securities, Gross Unrealized Gain (Loss) Net Unrealized Gains (Losses) Net Unrealized Gains (Losses) Available-for-sale Securities, Gross Unrealized Gain (Loss), Total Component of Other Income, Nonoperating [Axis] Component Of Other Income Nonoperating Name [Domain] Component of Other Income, Nonoperating, Name [Domain] Unrealized Holding Gains on Available for Sale Securities, Net of Taxes [Member] Unrealized Holding Gains On Available For Sale Securities Net Of Taxes [Member] Unrealized Gains [Member] Unrealized Holding Losses on Available for Sale Securities, Net of Taxes [Member] Unrealized Holding Losses On Available For Sale Securities Net Of Taxes [Member] Unrealized Losses [Member] Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax Unrealized gains (losses) Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax, Total Investment Income, Interest Interest income on investments Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments, Total Realized net gains on the sale of investments Income derived from investments in debt securities consisting of interest income and realized gains and losses from the sale of investments. Investment Income Interest income Interest income The amount of Senior Debt issued by a variable interest entity in which the Reporting Entity holds a variable interest. Senior Debt Issued By Variable Interest Entity Senior debt in the aggregate principal amount Subordinated Debt Subordinated Debt, Ending Balance Subordinated Debt, Beginning Balance Subordinated Debt, Total Face value of Subordinated Note The imputed interest rate on a non-interest bearing note receivable. Notes And Loans Receivable Imputed Interest Rate Imputed interest rate The term of a note receivable. Notes And Loans Receivable Term Subordinated Note maturity term, years Total advances made in accordance with a note arrangement. Advances Made Under Notes Receivable Advances to 2009 Entity Date of maturity of note receivable. Notes And Loans Receivable Maturity Date Revolving Note maturity date Notes, Loans and Financing Receivable, Net, Noncurrent Carrying value Notes, Loans and Financing Receivable, Net, Noncurrent, Total Incremental Common Shares Attributable to Share-based Payment Arrangements Shares assumed issued (less shares assumed purchased for treasury) for stock-based compensation Incremental Common Shares Attributable to Share-based Payment Arrangements, Total Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Shares excluded from calculation of diluted earnings per share Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Defined Benefit Plans [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] ESI Pension Plan [Member] Esi Pension Plan [Member] ESI Pension Plan [Member] ESI Excess Pension Plan [Member] Esi Excess Pension Plan [Member] ESI Excess Pension Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan, Service Cost Service cost Service cost included in net periodic pension benefit Defined Contribution Plan, Cost Recognized Contributions to the pension plans Employer contributions Defined Benefit Plan, Interest Cost Interest cost Defined Benefit Plan, Interest Cost Defined Benefit Plan, Expected Return on Plan Assets Expected return on assets Expected return on assets Defined Benefit Plan, Actuarial Net (Gains) Losses Recognized net actuarial loss Recognized net actuarial loss Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of prior service (credit) Defined Benefit Plan, Net Periodic Benefit Cost Cost incurred for providing different benefit Net periodic pension (benefit) Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Domain] Loss Contingency, Nature [Domain] Education Loan Under Two Thousand Nine Loan Program [Member] Education Loan Under Two Thousand Nine Loan Program [Member] Education Loan Under 2009 Loan Program [Member] Education Loan Under Two Thousand Seven Loan Program [Member] Education Loan Under Two Thousand Seven Loan Program [Member] Education Loan Under 2007 Loan Program [Member] Legal Entity [Axis] Entity [Domain] Entity [Domain] Variable Interest Entity Not Primary Beneficiary [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Loss Contingencies [Line Items] Maximum potential payments that entity could be required to reimburse issuer of surety bonds in the event that the issuer is required to make payment. Off Balance Sheet Obligation Surety Bond Face amount of surety bonds Loss Contingency, Estimate of Possible Loss Approximate claims and contingencies related to litigation, business transactions, guarantee arrangements and employee-related matters and others The total estimated initial principal balance of the loans that the party is expected to purchase that would be subject to the reporting entity's guarantee. Guarantor Obligations Total Principal Of Loans Subject To Guarantee Principal amount for private education loans Guarantor Obligations, Term PEAKS Senior Debt maturity date The maximum potential amount of future payments (undiscounted) the guarantor could be required to make for the principal amount of the Senior Debt issued by a third party that is covered under the guarantee. Guarantor Obligations Maximum Amount Of Debt Principal Exposure Maximum future payments for PEAKS Senior Debt The difference between the minimum estimated range of reasonably possible contingency loss and the amount recorded on the balance sheet date. Loss Contingency Range Of Possible Loss Less Than Amount Accrued Range of possible losses less than amount accrued Loss Contingency, Range of Possible Loss, Portion Not Accrued Range of possible losses greater than portion accrued Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Domain] Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Domain] Restricted Cash and Cash Equivalents, Cash and Cash Equivalents [Domain] Money Market Funds [Member] Money Market Funds [Member] U S Treasury Securities [Member] U.S. Treasury Obligations [Member]