Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory [Line Items]
Liability for Uncertainty in Income Taxes, Noncurrent	$ 11,000	$ 21,000
Inventory:
Remotely operated vehicle parts and components	93,770	98,624
Other inventory, primarily raw materials	72,590	76,120
Total	166,360	174,744
Other current assets:
Prepaid expenses	57,834	43,210
Angolan bonds	10,179	10,179
Total	68,013	53,389
Other Assets, Noncurrent	132,263	151,378
Accrued liabilities:
Payroll and related costs	105,956	137,001
Accounts Payable, Other, Current	56,982	54,387
Income taxes payable	36,024	36,996
Current operating lease liability	18,793	19,863
Other	81,151	89,434
Total	$ 298,906	$ 337,681