| Pay vs Performance Disclosure - USD ($) | 12 Months Ended |
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 |
| Pay vs Performance Disclosure [Table] | | | |
| Pay vs Performance [Table Text Block] | Value of Initial Fixed $100 Average Average Investment Based on: Summary Summary Compensation Peer Group Compensation Compensation Compensation Actually Paid Total Total Table Actually Paid Table Total for to Non-CEO Shareholder Shareholder Net Adjusted Year Total for CEO (1) to CEO (2) Non-CEO NEOs (3) NEOs (2) (3) Return Return (4) Income (5) EBITDA (6) 2022 $ 1,997,113 $ 2,919,364 $ 1,205,110 $ 1,604,033 $ 110.30 $ 92.68 $ 184,675 $ 291,336 2021 $ 1,843,058 $ 1,864,868 $ 1,099,912 $ 1,100,530 $ 89.48 $ 100.13 $ 260,344 $ 327,354 2020 $ 2,105,208 $ 1,830,647 $ 1,322,165 $ 1,222,327 $ 97.20 $ 124.90 $ 257,196 $ 323,830 (1) The dollar amounts reported are the amounts of total compensation reported for our CEO, Mr. Mueller , in the Summary Compensation Table for fiscal years 2022, 2021 and 2020. Mr. Mueller served as CEO for each of the years presented. (2) The dollar amounts reported represent the amount of “compensation actually paid” or “CAP”, as computed in accordance with SEC rules. The dollar amounts do not reflect the actual amounts of compensation paid to our CEO or other NEOs during the applicable years, but include (i) the year-end value of equity awards granted during the reported year, and (ii) the change in the value of equity awards that were unvested at the end of the prior year, measured through the date the awards vested or were forfeited, or through the end of the reported fiscal year. (3) For 2022 and 2021, reflects compensation information for our 2022 NEOs, other than our CEO, as described in the CD&A of this proxy statement (each of whom served as NEOs for both 2022 and 2021). For 2020, reflects compensation information for Dr. Meyer, Mr. Bachus, Mr. Mildenhall and Mr. Briggs. (4) Reflects cumulative total shareholder return for the eight companies included in the customized peer group used by GCE for purposes of Item 201 (e) of Regulation S-K under the Exchange Act in GCE’s Annual Report on Form 10-K for the year ended December 31, 2022. Those eight companies are: 2U Inc, Adtalem Global Education, Inc, Chegg Inc, Coursera Inc, John Wiley & Sons Inc, Laureate Education Inc, Pearson Plc and Strategic Education Inc. (5) The decline in net income between 2021 and 2022 is partially due to the lower interest income achieved as a result of the repayment to us by Grand Canyon University of a secured note payable that had been in place since 2018. (6) We defined Adjusted EBITDA for purposes of the Annual Cash Incentive Plan in a manner consistent with the definition we use when reporting our financial results. See Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations – Adjusted EBITDA (Non- GAAP Financial Measure), beginning on page 58 of our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 for information regarding our use and calculation of Adjusted EBITDA. | | |
| Company Selected Measure Name | Adjusted EBITDA | | |
| Named Executive Officers, Footnote [Text Block] | (1) The dollar amounts reported are the amounts of total compensation reported for our CEO, Mr. Mueller , in the Summary Compensation Table for fiscal years 2022, 2021 and 2020. Mr. Mueller served as CEO for each of the years presented. (3) For 2022 and 2021, reflects compensation information for our 2022 NEOs, other than our CEO, as described in the CD&A of this proxy statement (each of whom served as NEOs for both 2022 and 2021). For 2020, reflects compensation information for Dr. Meyer, Mr. Bachus, Mr. Mildenhall and Mr. Briggs. | | |
| Peer Group Issuers, Footnote [Text Block] | (4) Reflects cumulative total shareholder return for the eight companies included in the customized peer group used by GCE for purposes of Item 201 (e) of Regulation S-K under the Exchange Act in GCE’s Annual Report on Form 10-K for the year ended December 31, 2022. Those eight companies are: 2U Inc, Adtalem Global Education, Inc, Chegg Inc, Coursera Inc, John Wiley & Sons Inc, Laureate Education Inc, Pearson Plc and Strategic Education Inc. | | |
| PEO Total Compensation Amount | $ 1,997,113 | $ 1,843,058 | $ 2,105,208 |
| PEO Actually Paid Compensation Amount | $ 2,919,364 | 1,864,868 | 1,830,647 |
| Adjustment To PEO Compensation, Footnote [Text Block] | To calculate the amounts in the “Compensation Actually Paid to CEO” column in the table above, the following amounts were deducted from and added to (as applicable) our CEO’s “Total” compensation as reported in the Summary Compensation Table (SCT): Summary Compensation Reported Equity Award Table Total for Value of Equity Adjustments Compensation Year CEO Awards for CEO (1) for CEO (2) Actually Paid to CEO 2022 $ 1,997,113 $ (1,211,488) $ 2,133,739 $ 2,919,364 2021 $ 1,843,058 $ (1,211,575) $ 1,233,385 $ 1,864,868 2020 $ 2,105,208 $ (1,211,533) $ 936,972 $ 1,830,647 (1) Represents the grant date fair value of the equity awards to our CEO, as reported in the “Stock Awards” column in the SCT for each applicable year. (2) Represents the adjustments to equity awards granted to our CEO to arrive at CAP, as itemized in the table below. No awards vested in the year they were granted. Fair Value of Equity Awards for CEO 2022 2021 2020 As of year-end for awards granted during the year $ 1,542,425 $ 1,207,911 $ 1,341,808 Year-over-year increase (decrease) of unvested awards granted in prior years $ 555,228 $ (209,339) $ (83,431) Increase (decrease) from prior fiscal year-end for awards that vested during the year $ 36,086 $ 234,813 $ (321,405) Total Equity Award Adjustments $ 2,133,739 $ 1,233,385 $ 936,972 | | |
| Non-PEO NEO Average Total Compensation Amount | $ 1,205,110 | 1,099,912 | 1,322,165 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,604,033 | 1,100,530 | 1,222,327 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | To calculate the amounts in the “Average Compensation Actually Paid to Non-CEO NEOs” column in the table above, the following amounts were deducted from and added to (as applicable) the average of the “Total” compensation of our non-CEO named executive officers for each applicable year, as reported in the SCT for that year: Average Summary Average Average Compensation Reported Value of Equity Award Average Table Total for Equity Awards for Adjustments Compensation Actually Year Non-CEO NEOs Non-CEO NEOs (1) for Non-CEO NEOs (2) Paid to Non-CEO NEOs 2022 $ 1,205,110 $ (560,722) $ 959,645 $ 1,604,033 2021 $ 1,099,912 $ (553,324) $ 553,942 $ 1,100,530 2020 $ 1,322,165 $ (609,865) $ 510,027 $ 1,222,327 (1) Represents the average of the grant date fair value of the equity awards to our named executive officers (other than our CEO), as reported in the “Stock Awards” column in the SCT for each applicable year. (2) Represents adjustments for the equity awards granted to our named executive officers (other than our CEO) to arrive at CAP, as itemized in the table below. No awards vested in the year they were granted. Fair Value of Equity Awards for Non-CEO NEOs 2022 2021 2020 As of year-end for awards granted during the year $ 713,892 $ 551,651 $ 675,443 Year-over-year increase (decrease) of unvested awards granted in prior years $ 232,133 $ (79,117) $ (34,816) Increase (decrease) from prior fiscal year-end for awards that vested during the year $ 13,620 $ 81,408 $ (130,600) Total Equity Award Adjustments $ 959,645 $ 553,942 $ 510,027 | | |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | | | |
| Compensation Actually Paid vs. Net Income [Text Block] | | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | | | |
| Total Shareholder Return Vs Peer Group [Text Block] | | | |
| Tabular List [Table Text Block] | Most Important Financial Performance Measures ● Adjusted EBITDA ● Service Revenue ● Return on Equity ● Free Cash Flow ● Total Shareholder Return ● As Adjusted Non-GAAP Diluted EPS ● Net Income | | |
| Total Shareholder Return Amount | $ 110.30 | 89.48 | 97.20 |
| Peer Group Total Shareholder Return Amount | 92.68 | 100.13 | 124.90 |
| Net Income (Loss) | $ 184,675 | $ 260,344 | $ 257,196 |
| Company Selected Measure Amount | 291,336 | 327,354 | 323,830 |
| PEO Name | Mr. Mueller | | |
| Measure [Axis]: 1 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Adjusted EBITDA | | |
| Non-GAAP Measure Description [Text Block] | (6) We defined Adjusted EBITDA for purposes of the Annual Cash Incentive Plan in a manner consistent with the definition we use when reporting our financial results. See Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations – Adjusted EBITDA (Non- GAAP Financial Measure), beginning on page 58 of our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 for information regarding our use and calculation of Adjusted EBITDA. | | |
| Measure [Axis]: 2 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Service Revenue | | |
| Measure [Axis]: 3 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Return on Equity | | |
| Measure [Axis]: 4 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Free Cash Flow | | |
| Measure [Axis]: 5 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Total Shareholder Return | | |
| Measure [Axis]: 6 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | As Adjusted Non-GAAP Diluted EPS | | |
| Measure [Axis]: 7 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Net Income | | |
| PEO [Member] | Reported Value of Equity Awards | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ (1,211,488) | $ (1,211,575) | $ (1,211,533) |
| PEO [Member] | As of year-end for awards granted during the year | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 1,542,425 | 1,207,911 | 1,341,808 |
| PEO [Member] | Year-over-year increase (decrease) of unvested awards granted in prior years | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 555,228 | (209,339) | (83,431) |
| PEO [Member] | Increase (decrease) from prior fiscal year-end for awards that vested during the year | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 36,086 | 234,813 | (321,405) |
| PEO [Member] | Equity Award Adjustments | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 2,133,739 | 1,233,385 | 936,972 |
| Non-PEO NEO [Member] | Reported Value of Equity Awards | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (560,722) | (553,324) | (609,865) |
| Non-PEO NEO [Member] | As of year-end for awards granted during the year | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 713,892 | 551,651 | 675,443 |
| Non-PEO NEO [Member] | Year-over-year increase (decrease) of unvested awards granted in prior years | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 232,133 | (79,117) | (34,816) |
| Non-PEO NEO [Member] | Increase (decrease) from prior fiscal year-end for awards that vested during the year | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 13,620 | 81,408 | (130,600) |
| Non-PEO NEO [Member] | Equity Award Adjustments | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ 959,645 | $ 553,942 | $ 510,027 |
