Revenue from Contracts with Customers (Narrative 2) (Details) - Long-term Contract with Customer [Member] - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-10-01 $ in Millions |
Sep. 30, 2026
USD ($)
|
|---|---|
| Kaplan International [Member] | |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | |
| Revenue, Remaining Performance Obligation, Amount | $ 186.7 |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period | 3 years |
| Supplemental Education [Member] | |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | |
| Revenue, Remaining Performance Obligation, Amount | $ 4.3 |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period | 12 months |