| 5.   Accumulated Other Comprehensive Income (Loss) Accumulated other comprehensive income (loss) for the three months ended March 31, 2025 was as follows (in thousands):  
|  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Three Months Ended March 31, 2025 |  |  
|  |      |  |  |      |  |  |  | Change |  |  
|  |  | Accumulated |  | Change |  | Related to |  |  
|  |  | Other |  | Related to |  | Shipboard |  |  
|  |  | Comprehensive |  | Cash Flow |  | Retirement |  |  
|  |      | Income (Loss) |      | Hedges |  |  Plan |  |  
| Accumulated other comprehensive income (loss) at beginning of period |  | $ |  (507,039) |  | $ |  (514,243) |  | $ |  7,204 |    |  
| Current period other comprehensive income before reclassifications |  |   |  30,825 |  |   |  30,825 |    |   |  — |    |  
| Amounts reclassified into earnings |  |   |  4,089 |  |   |  4,073 | (1) |   |  16 | (2) |  
| Accumulated other comprehensive income (loss) at end of period |  | $ |  (472,125) |  | $ |  (479,345) | (3) | $ |  7,220 |    |   Accumulated other comprehensive income (loss) for the three months ended March 31, 2024 was as follows (in thousands):  
|  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Three Months Ended March 31, 2024 |  |  
|  |      |  |  |      |  |  |  | Change |   |  
|  |  | Accumulated |  | Change |  | Related to |  |  
|  |  | Other |  | Related to |  | Shipboard |  |  
|  |  | Comprehensive |  | Cash Flow |  | Retirement |  |  
|  |      | Income (Loss) |      | Hedges |  |  Plan |  |  
| Accumulated other comprehensive income (loss) at beginning of period |   | $ |  (508,438) |  | $ |  (508,524) |  | $ |  86 |   |  
| Current period other comprehensive income before reclassifications |   |   |  47,253 |   |   |  47,253 |    |   |  — |   |  
| Amounts reclassified into earnings |   |   |  (3,238) |   |   |  (3,333) | (1) |   |  95 | (2) |  
| Accumulated other comprehensive income (loss) at end of period |   | $ |  (464,423) |   | $ |  (464,604) |  | $ |  181 |   |  
| (1) | We refer you to Note 8 – “Fair Value Measurements and Derivatives” for the affected line items in the consolidated statements of operations. | 
 
| (2) | Amortization of prior-service cost and actuarial loss reclassified to other income (expense), net. | 
 
| (3) | Includes $24.2 million of losses expected to be reclassified into earnings in the next 12 months. | 
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