| In millions, except per share items | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 |
| | 20-F | 20-F | 20-F | 20-F | 20-F | 20-F | 20-F | 20-F |
| Revenues | | | | | | | | |
| Operating lease revenue | 293.7 | 464.4 | | | | | | |
| Operating lease revenue | | | 399.5 | 346.9 | 313.6 | 429.7 | 406.6 | 351.8 |
| Finance lease revenue | 0.6 | 0.6 | 0.7 | 0.7 | 2.1 | 0.3 | | |
| Finance lease revenue | 0.6 | 0.6 | 0.7 | 0.7 | 2.1 | 0.3 | | |
| Gain on sale of aircraft | 36.0 | 97.3 | 13.4 | | | | 14.8 | 5.4 |
| Interest and other income | 4.1 | 12.7 | 4.7 | 1.2 | 1.7 | 2.3 | 0.7 | 1.9 |
| Total revenues | 334.4 | 575.0 | 418.3 | 353.3 | 345.0 | 462.4 | 425.5 | 360.6 |
| Total revenues growth | -41.9% | 37.5% | 18.4% | 2.4% | -25.4% | 8.7% | 18.0% | |
| Expenses | | | | | | | | |
| Depreciation | 129.6 | 140.8 | 144.1 | 133.2 | 120.5 | 159.7 | 167.0 | 138.3 |
| Flight equipment impairment | 115.0 | | | 22.0 | 96.1 | 66.1 | 1.2 | 6.2 |
| Interest expense | -103.3 | -137.1 | -144.7 | -127.8 | -123.2 | -145.4 | -142.5 | -120.4 |
| Selling, general and administrative | 30.9 | 35.3 | 31.2 | 30.7 | 30.1 | 33.7 | 41.0 | 39.6 |
| Provision for uncollectible operating lease receivables | 4.0 | | | | | | | |
| Loss (gain) on derivatives | 1.6 | 2.7 | -2.4 | -0.2 | 0.1 | 4.1 | | |
| Fair value loss on marketable securities | 13.0 | | | | | | | |
| Loss on modification and extinguishment of debt | 1.9 | 9.6 | 2.5 | 23.3 | 9.2 | 17.5 | | |
| Maintenance and other costs | 6.6 | 3.1 | 2.5 | 2.5 | 2.3 | 7.6 | 7.1 | 15.5 |
| Total expenses | 405.9 | 328.6 | 322.7 | 339.3 | 381.4 | 434.2 | 356.7 | 303.6 |
| Net income (loss) before provision (benefit) for income taxes | -71.6 | 246.4 | 95.6 | 13.9 | -36.4 | 28.2 | 68.9 | 57.1 |
| Provision (benefit) for income taxes | -4.1 | 20.5 | 9.9 | 11.3 | -7.3 | 5.4 | 8.7 | 3.1 |
| Net income (loss) | -67.4 | 225.9 | 85.7 | 2.6 | -29.1 | 22.8 | 60.2 | 53.9 |
| |
| Weighted average number of shares: | | | | | | | | |
| Basic (in shares) | 30.6 | 31.6 | 29.7 | 30.3 | 33.2 | 41.2 | 41.4 | 34.1 |
| Diluted (in shares) | 30.6 | 31.7 | 29.8 | 30.4 | 33.2 | 41.3 | 41.5 | 34.2 |
| |
| Earnings (loss) per share: | | | | | | | | |
| Basic (in dollars per share) | ($2.21) | $7.15 | $2.88 | $0.09 | ($0.88) | $0.52 | $1.42 | $1.55 |
| Diluted (in dollars per share) | ($2.21) | $7.12 | $2.88 | $0.09 | ($0.88) | $0.52 | $1.42 | $1.55 |