Selected Balance Sheet Information (Details 2) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Inventory for remotely operated vehicles	$ 97,313	$ 118,236
Inventory, Work in Process and Raw Materials	117,969	161,894
Inventory	215,282	280,130
Prepaid Expense, Current	64,901	42,523
Intangible Assets, Net (Excluding Goodwill)	85,293	87,801
Investments and Other Noncurrent Assets	68,280	59,130
Cash surrender value of life insurance policies	54,987	60,160
Equity Method Investments	49,094	39,826
Deferred Income Tax Assets, Net	24,633	12,187
Other	34,458	11,807
Other non-current assets	316,745	270,911
Payroll and related costs	101,989	141,485
Accrued job costs	58,823	59,331
Deferred revenue, including billings in excess of revenue recognized	63,040	122,223
Accrued Income Taxes, Current	30,589	35,126
Other	95,817	72,606
Accrued Liabilities, Current	350,258	430,771
Deferred tax liabilities	42,040	236,113
Supplemental Executive Retirement Plan	45,037	49,163
Accrued post-employment benefit obligations	3,352	4,648
Other	40,894	22,326
Accounts Payable and Accrued Liabilities, Noncurrent	$ 131,323	$ 312,250