| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| REVENUE: | | | | | | | | |
| Total revenue | 725.7 | 602.7 | 455.4 | 438.7 | 451.2 | 481.2 | 457.0 | 355.4 |
| Total revenue growth | 20.4% | 32.3% | 3.8% | -2.8% | -6.2% | 5.3% | 28.6% | 5.7% |
| OPERATING EXPENSES (excluding depreciation and amortization unless otherwise indicated): | | | | | | | | |
| Cost of services | | | | | | | | |
| Transaction-related charges | 4.8 | 10.2 | 1.6 | 0.2 | 2.6 | 1.0 | 18.1 | 7.2 |
| Restructuring expenses | | | | | 0.5 | 1.2 | | |
| Depreciation and amortization | 148.2 | 110.5 | 88.3 | 89.1 | 85.7 | 86.9 | 76.0 | 56.9 |
| (Gain) Loss on disposition of long-lived assets | 4.4 | 2.8 | 21.6 | 2.8 | -26.4 | 0.1 | | |
| Total operating expenses | 717.8 | 617.7 | 446.3 | 425.3 | 390.2 | 425.9 | 405.7 | 276.8 |
| Income from operations | 7.9 | -15.0 | 9.2 | 13.4 | 61.0 | 55.3 | 51.3 | 78.6 |
| Operating margin | 1.1% | -2.5% | 2.0% | 3.0% | 13.5% | 11.5% | 11.2% | 22.1% |
| |
| OTHER INCOME (EXPENSE) | | | | | | | | |
| Interest income | 0.2 | 0.1 | 0.4 | 2.3 | 1.8 | | | |
| Interest expense | -20.4 | -9.6 | -5.3 | -5.0 | -8.0 | | | |
| Other income | 4.2 | 1.8 | -4.2 | -4.6 | -1.1 | 0.0 | -1.8 | 0.1 |
| Other income (expense) | -16.0 | -7.7 | -9.1 | -7.3 | -7.3 | -7.8 | -15.0 | -22.4 |
| LOSS BEFORE INCOME TAXES | -8.1 | -22.7 | 0.1 | 6.1 | 53.7 | 47.6 | 45.4 | 56.2 |
| Income tax (benefit) expense | -0.5 | -1.9 | 0.8 | 4.1 | 18.9 | -1.3 | 21.2 | 24.1 |
| NET LOSS | -7.6 | -20.8 | -0.7 | 2.0 | 34.9 | 48.9 | 24.2 | 33.2 |
| Net loss attributable to noncontrolling interests, net of tax (benefit) expense of $(0.7) million, $0 million, $(1.2) million and $(0.5) million respectively | 1.9 | -1.3 | -13.4 | -12.8 | -15.1 | -17.4 | -12.1 | -16.2 |
| NET INCOME (LOSS) ATTRIBUTABLE TO ATN INTERNATIONAL, INC. STOCKHOLDERS | -5.6 | -22.1 | -14.1 | -10.8 | 19.8 | 31.5 | 12.1 | 16.9 |
| |
| NET LOSS PER WEIGHTED AVERAGE SHARE ATTRIBUTABLE TO ATN INTERNATIONAL, INC. STOCKHOLDERS: | | | | | | | | |
| NET LOSS PER WEIGHTED AVERAGE SHARE ATTRIBUTABLE TO ATN INTERNATIONAL, INC. STOCKHOLDERS: | | | | | | | | |
| Basic (in dollars per share) | ($0.67) | ($1.52) | ($0.89) | ($0.68) | $1.24 | $1.95 | $0.75 | $1.06 |
| Diluted (in dollars per share) | ($0.67) | ($1.52) | ($0.89) | ($0.68) | $1.24 | $1.94 | $0.75 | $1.06 |
| |
| WEIGHTED AVERAGE COMMON SHARES OUTSTANDING: | | | | | | | | |
| Basic (in shares) | 15.8 | 15.9 | 15.9 | 16.0 | 16.0 | 16.1 | 16.1 | 16.0 |
| Diluted (in shares) | 15.8 | 15.9 | 15.9 | 16.0 | 16.0 | 16.2 | 16.2 | 16.1 |
| |
| DIVIDENDS PER SHARE APPLICABLE TO COMMON STOCK | $0.72 | $0.68 | $0.68 | $0.68 | $0.68 | $1.02 | $1.32 | $1.22 |