Accumulated other comprehensive income (loss) - Amounts in OCI (Details) - USD ($)
$ in Millions |
3 Months Ended |
6 Months Ended |
Jun. 30, 2026 |
Mar. 31, 2026 |
Jun. 30, 2025 |
Mar. 31, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
$ 6.4
|
|
$ 82.2
|
|
$ 7.6
|
$ 118.5
|
| Amounts Arising During the Current Period, Income Tax |
(0.3)
|
|
8.2
|
|
(3.3)
|
11.9
|
| Amounts Reclassified to Net Income (Loss), Pretax |
0.7
|
|
2.4
|
|
2.9
|
0.1
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
(0.3)
|
|
0.4
|
|
(0.3)
|
1.2
|
| Other comprehensive income |
6.5
|
$ 0.4
|
93.2
|
$ 38.5
|
6.9
|
131.7
|
| Cost of revenues |
1,026.2
|
|
976.7
|
|
2,045.6
|
1,916.2
|
| Selling, general and administrative expenses |
232.6
|
|
184.5
|
|
483.4
|
370.8
|
| Interest and other nonoperating expense |
2.5
|
|
(1.8)
|
|
3.4
|
(9.7)
|
| Interest expense |
62.9
|
|
60.9
|
|
126.4
|
118.4
|
| AOCI Attributable to Parent |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
6.5
|
|
78.3
|
|
8.7
|
113.9
|
| Amounts Arising During the Current Period, Income Tax |
(0.3)
|
|
8.2
|
|
(3.3)
|
11.9
|
| Amounts Reclassified to Net Income (Loss), Pretax |
0.7
|
|
2.4
|
|
2.9
|
0.1
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
(0.3)
|
|
0.4
|
|
(0.3)
|
1.2
|
| Other comprehensive income |
6.6
|
$ 1.4
|
89.3
|
$ 37.8
|
8.0
|
127.1
|
| Benefit plan adjustments |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
(0.2)
|
|
(4.4)
|
|
0.2
|
(7.8)
|
| Amounts Arising During the Current Period, Income Tax |
0.0
|
|
1.3
|
|
(1.0)
|
2.2
|
| Amounts Reclassified to Net Income (Loss), Pretax |
3.0
|
|
1.6
|
|
6.2
|
2.8
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
(0.7)
|
|
(0.4)
|
|
(1.5)
|
(0.7)
|
| Other comprehensive income |
2.1
|
|
(1.9)
|
|
3.9
|
(3.5)
|
| Foreign currency translation adjustments |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
6.0
|
|
84.8
|
|
8.1
|
123.5
|
| Amounts Arising During the Current Period, Income Tax |
0.0
|
|
8.0
|
|
(2.2)
|
10.9
|
| Amounts Reclassified to Net Income (Loss), Pretax |
(1.3)
|
|
(1.2)
|
|
(2.8)
|
(2.4)
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
0.3
|
|
0.3
|
|
0.7
|
0.6
|
| Other comprehensive income |
5.0
|
|
91.9
|
|
3.8
|
132.6
|
| Gains (losses) on available-for-sale securities |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
0.2
|
|
(1.8)
|
|
(0.8)
|
(1.4)
|
| Amounts Arising During the Current Period, Income Tax |
(0.2)
|
|
(1.2)
|
|
0.2
|
(1.3)
|
| Amounts Reclassified to Net Income (Loss), Pretax |
0.0
|
|
4.1
|
|
1.6
|
4.3
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
(0.1)
|
|
0.0
|
|
0.0
|
0.2
|
| Other comprehensive income |
(0.1)
|
|
1.1
|
|
1.0
|
1.8
|
| Gains (Losses) on Cash Flow Hedges |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
0.5
|
|
(0.3)
|
|
1.2
|
(0.4)
|
| Amounts Arising During the Current Period, Income Tax |
(0.1)
|
|
0.1
|
|
(0.3)
|
0.1
|
| Amounts Reclassified to Net Income (Loss), Pretax |
(1.0)
|
|
(2.1)
|
|
(2.1)
|
(4.6)
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
0.2
|
|
0.5
|
|
0.5
|
1.1
|
| Other comprehensive income |
(0.4)
|
|
(1.8)
|
|
(0.7)
|
(3.8)
|
| Gains (Losses) on Cash Flow Hedges | Reclassification out of accumulated other comprehensive income |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Interest expense |
(1.0)
|
|
(2.1)
|
|
(2.1)
|
(4.6)
|
| AOCI Attributable to Noncontrolling Interest |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
(0.1)
|
|
3.9
|
|
(1.1)
|
4.6
|
| Amounts Arising During the Current Period, Income Tax |
0.0
|
|
0.0
|
|
0.0
|
0.0
|
| Amounts Reclassified to Net Income (Loss), Pretax |
0.0
|
|
0.0
|
|
0.0
|
0.0
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
0.0
|
|
0.0
|
|
0.0
|
0.0
|
| Other comprehensive income |
(0.1)
|
|
3.9
|
|
(1.1)
|
4.6
|
| Foreign currency translation adjustments |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
(0.1)
|
|
3.9
|
|
(1.1)
|
4.6
|
| Amounts Arising During the Current Period, Income Tax |
0.0
|
|
0.0
|
|
0.0
|
0.0
|
| Amounts Reclassified to Net Income (Loss), Pretax |
0.0
|
|
0.0
|
|
0.0
|
0.0
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
0.0
|
|
0.0
|
|
0.0
|
0.0
|
| Other comprehensive income |
(0.1)
|
|
3.9
|
|
(1.1)
|
4.6
|
| Benefit plan adjustments |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
(0.2)
|
|
(4.4)
|
|
0.2
|
(7.8)
|
| Amounts Arising During the Current Period, Income Tax |
0.0
|
|
1.3
|
|
(1.0)
|
2.2
|
| Amounts Reclassified to Net Income (Loss), Pretax |
3.0
|
|
1.6
|
|
6.2
|
2.8
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
(0.7)
|
|
(0.4)
|
|
(1.5)
|
(0.7)
|
| Other comprehensive income |
2.1
|
|
(1.9)
|
|
3.9
|
(3.5)
|
| Benefit plan adjustments | Reclassification out of accumulated other comprehensive income |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Cost of revenues |
1.8
|
|
1.7
|
|
3.7
|
3.3
|
| Selling, general and administrative expenses |
0.5
|
|
0.5
|
|
1.1
|
1.0
|
| Interest and other nonoperating expense |
4.1
|
|
0.7
|
|
8.3
|
0.8
|
| Foreign currency translation adjustments |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
5.9
|
|
88.7
|
|
7.0
|
128.1
|
| Amounts Arising During the Current Period, Income Tax |
0.0
|
|
8.0
|
|
(2.2)
|
10.9
|
| Amounts Reclassified to Net Income (Loss), Pretax |
(1.3)
|
|
(1.2)
|
|
(2.8)
|
(2.4)
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
0.3
|
|
0.3
|
|
0.7
|
0.6
|
| Other comprehensive income |
4.9
|
|
95.8
|
|
2.7
|
137.2
|
| Gains (losses) on available-for-sale securities |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
0.2
|
|
(1.8)
|
|
(0.8)
|
(1.4)
|
| Amounts Arising During the Current Period, Income Tax |
(0.2)
|
|
(1.2)
|
|
0.2
|
(1.3)
|
| Amounts Reclassified to Net Income (Loss), Pretax |
0.0
|
|
4.1
|
|
1.6
|
4.3
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
(0.1)
|
|
0.0
|
|
0.0
|
0.2
|
| Other comprehensive income |
(0.1)
|
|
1.1
|
|
1.0
|
1.8
|
| Gains (losses) on cash flow hedges |
|
|
|
|
|
|
| Other Comprehensive Income Loss [Line Items] |
|
|
|
|
|
|
| Amounts Arising During the Current Period, Pretax |
0.5
|
|
(0.3)
|
|
1.2
|
(0.4)
|
| Amounts Arising During the Current Period, Income Tax |
(0.1)
|
|
0.1
|
|
(0.3)
|
0.1
|
| Amounts Reclassified to Net Income (Loss), Pretax |
(1.0)
|
|
(2.1)
|
|
(2.1)
|
(4.6)
|
| Amounts Reclassified to Net Income (Loss), Income Tax |
0.2
|
|
0.5
|
|
0.5
|
1.1
|
| Other comprehensive income |
$ (0.4)
|
|
$ (1.8)
|
|
$ (0.7)
|
$ (3.8)
|