v3.26.1
Segment Information (Schedule Of Segment Reporting Information) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Segment Reporting [Line Items]            
Revenues (exclusive of reimbursable revenues) $ 502.3   $ 572.3 $ 932.4 $ 1,150.1  
Reimbursable revenues 36.9   42.9 72.2 85.8  
Total operating revenues 539.2   615.2 1,004.6 1,235.9  
Operating expenses:            
Contract Drilling Expenses Exclusive of Depreciation and Reimbursable Expenses 380.4   355.2 720.8 729.2  
Reimbursable expenses 35.1   40.5 68.1 81.5  
Total contract drilling expenses (exclusive of depreciation) 415.5   395.7 788.9 810.7  
Depreciation 44.6   35.5 87.3 68.6  
General and administrative 27.2   18.8 52.5 43.2  
Business Combination, Acquisition-Related Cost, Expense 11.4   0.0 25.0 0.0  
Other operating (income) loss 0.0 $ (2.8) 0.0 (2.8) 7.8  
Costs and Expenses 498.7   450.0 950.9 930.3  
Equity in earnings of ARO (10.6)   1.1 (17.4) (1.5)  
OPERATING INCOME 51.1   164.1 71.1 307.1  
Property and equipment, net (2,233.8)   (2,021.6) (2,233.8) (2,021.6) $ (2,088.8)
Capital expenditures 105.5   67.2 206.4 167.4  
Operating Segments | Floaters            
Segment Reporting [Line Items]            
Revenues (exclusive of reimbursable revenues) 279.0   319.7 471.6 675.7  
Reimbursable revenues 11.0   7.2 16.0 16.1  
Total operating revenues 290.0   326.9 487.6 691.8  
Operating expenses:            
Contract Drilling Expenses Exclusive of Depreciation and Reimbursable Expenses 167.9   176.3 318.5 380.3  
Reimbursable expenses 10.5   6.7 15.4 15.0  
Total contract drilling expenses (exclusive of depreciation) 178.4   183.0 333.9 395.3  
Depreciation 17.2   14.6 32.9 28.8  
General and administrative 0.0   0.0 0.0 0.0  
Business Combination, Acquisition-Related Cost, Expense 0.0     0.0    
Other operating (income) loss       (2.8) 7.8  
Costs and Expenses 195.6   197.6 364.0 431.9  
Equity in earnings of ARO 0.0   0.0 0.0 0.0  
OPERATING INCOME 94.4   129.3 123.6 259.9  
Property and equipment, net (1,320.2)   (1,183.3) (1,320.2) (1,183.3)  
Capital expenditures 58.4   25.2 113.7 52.2  
Operating Segments | Jackups            
Segment Reporting [Line Items]            
Revenues (exclusive of reimbursable revenues) 183.4   212.0 379.2 397.9  
Reimbursable revenues 13.8   26.0 28.2 53.7  
Total operating revenues 197.2   238.0 407.4 451.6  
Operating expenses:            
Contract Drilling Expenses Exclusive of Depreciation and Reimbursable Expenses 143.9   124.3 272.7 241.0  
Reimbursable expenses 12.7   24.3 25.9 50.7  
Total contract drilling expenses (exclusive of depreciation) 156.6   148.6 298.6 291.7  
Depreciation 16.2   14.6 32.7 27.3  
General and administrative 0.0   0.0 0.0 0.0  
Business Combination, Acquisition-Related Cost, Expense 0.0     0.0    
Other operating (income) loss       0.0 0.0  
Costs and Expenses 172.8   163.2 331.3 319.0  
Equity in earnings of ARO 0.0   0.0 0.0 0.0  
OPERATING INCOME 24.4   74.8 76.1 132.6  
Property and equipment, net (636.3)   (643.4) (636.3) (643.4)  
Capital expenditures 21.6   39.8 44.6 110.0  
Operating Segments | ARO            
Segment Reporting [Line Items]            
Revenues (exclusive of reimbursable revenues) 126.9   139.9 254.3 274.6  
Reimbursable revenues 0.0   0.0 0.0 0.0  
Total operating revenues 126.9   139.9 254.3 274.6  
Operating expenses:            
Contract Drilling Expenses Exclusive of Depreciation and Reimbursable Expenses 71.6   96.4 146.7 182.0  
Reimbursable expenses 0.0   0.0 0.0 0.0  
Total contract drilling expenses (exclusive of depreciation) 71.6   96.4 146.7 182.0  
Depreciation 22.0   28.7 46.9 58.2  
General and administrative 10.6   6.6 17.7 12.9  
Business Combination, Acquisition-Related Cost, Expense 0.0     0.0    
Other operating (income) loss       0.0 0.0  
Costs and Expenses 104.2   131.7 211.3 253.1  
Equity in earnings of ARO 0.0   0.0 0.0 0.0  
OPERATING INCOME 22.7   8.2 43.0 21.5  
Property and equipment, net (1,270.4)   (1,214.9) (1,270.4) (1,214.9)  
Capital expenditures 39.3   14.1 71.6 22.1  
Operating Segments | Other            
Segment Reporting [Line Items]            
Revenues (exclusive of reimbursable revenues) 39.9   40.6 81.6 76.5  
Reimbursable revenues 12.1   9.7 28.0 16.0  
Total operating revenues 52.0   50.3 109.6 92.5  
Operating expenses:            
Contract Drilling Expenses Exclusive of Depreciation and Reimbursable Expenses 27.4   17.4 50.1 33.4  
Reimbursable expenses 11.9   9.5 26.8 15.8  
Total contract drilling expenses (exclusive of depreciation) 39.3   26.9 76.9 49.2  
Depreciation 6.1   2.8 12.3 5.6  
General and administrative 0.0   0.0 0.0 0.0  
Business Combination, Acquisition-Related Cost, Expense 0.0     0.0    
Other operating (income) loss       0.0 0.0  
Costs and Expenses 45.4   29.7 89.2 54.8  
Equity in earnings of ARO 0.0   0.0 0.0 0.0  
OPERATING INCOME 6.6   20.6 20.4 37.7  
Property and equipment, net (224.1)   (133.6) (224.1) (133.6)  
Capital expenditures 24.1   0.0 46.6 0.0  
Corporate, Non-Segment | Reconciling Items            
Segment Reporting [Line Items]            
Revenues (exclusive of reimbursable revenues) (126.9)   (139.9) (254.3) (274.6)  
Reimbursable revenues 0.0   0.0 0.0 0.0  
Total operating revenues (126.9)   (139.9) (254.3) (274.6)  
Operating expenses:            
Contract Drilling Expenses Exclusive of Depreciation and Reimbursable Expenses (30.4)   (59.2) (67.2) (107.5)  
Reimbursable expenses 0.0   0.0 0.0 0.0  
Total contract drilling expenses (exclusive of depreciation) (30.4)   (59.2) (67.2) (107.5)  
Depreciation (16.9)   (25.2) (37.5) (51.3)  
General and administrative 16.6   12.2 34.8 30.3  
Business Combination, Acquisition-Related Cost, Expense 11.4     25.0    
Other operating (income) loss       0.0 0.0  
Costs and Expenses (19.3)   (72.2) (44.9) (128.5)  
Equity in earnings of ARO (10.6)   1.1 (17.4) (1.5)  
OPERATING INCOME (97.0)   (68.8) (192.0) (144.6)  
Property and equipment, net 1,217.2   1,153.6 1,217.2 1,153.6  
Capital expenditures $ (37.9)   $ (11.9) $ (70.1) $ (16.9)