| Line Item | Jun 30, 2026 | Mar 31, 2026 | Dec 31, 2025 | Sep 30, 2025 | Jun 30, 2025 | Mar 31, 2025 | Dec 31, 2024 | Sep 30, 2024 | Jun 30, 2024 | Mar 31, 2024 | Dec 31, 2023 | Sep 30, 2023 | Jun 30, 2023 | Mar 31, 2023 | Dec 31, 2022 | Sep 30, 2022 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Service revenues | ||||||||||||||||
| YoY growth | -2.4% | -3.8% | -5.8% | -7.5% | ||||||||||||
| Costs of services | ||||||||||||||||
| Gross margin | ||||||||||||||||
| % of revenue | 35.5% | 36.9% | 37.6% | 37.2% | ||||||||||||
| Selling, general and administrative expenses | ||||||||||||||||
| Operating (loss) income | ||||||||||||||||
| % of revenue | -4.7% | 2.8% | 1.7% | 1.0% | ||||||||||||
| (Income) loss from investments held in employee deferred compensation trusts (which is completely offset by related costs and expenses - Note A) | ||||||||||||||||
| Interest income, net | ||||||||||||||||
| Income before income taxes | ||||||||||||||||
| Provision for income taxes | ||||||||||||||||
| Net income | ||||||||||||||||
| % of revenue | 2.0% | 1.1% | 2.4% | 3.2% | ||||||||||||
| Basic (in usd per share) | ||||||||||||||||
| Diluted (in usd per share) |