Business Combinations - Total Acquisition Date Fair Value (Details) - USD ($) $ in Thousands	Aug. 17, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total Acquisition Date Fair Value
Goodwill		$ 639,484	$ 639,484	$ 639,188
CBR
Business Acquisition [Line Items]
Cash consideration	$ 700,000
Estimated working capital, indebtedness and other adjustments	(17,837)
Purchase price paid at closing	682,163
Cash paid on finalization of the net working capital, indebtedness and other adjustments	193
Total purchase price	682,356
Total Acquisition Date Fair Value
Accounts receivable	8,660
Inventories	3,825
Prepaid and other current assets	8,480
Restricted cash - short-term	30,752
Property, plant and equipment	29,401
Deferred income tax assets	5,062
Other long-term assets	496
Accounts payable	(2,853)
Accrued expenses	(13,770)
Deferred revenues - short-term	(3,100)
Payable to former CBR shareholders	(37,947)
Deferred income tax liabilities	(149,873)
Other long-term liabilities	(506)
Total estimated identifiable net assets	240,985
Goodwill	441,371
Total	682,356
CBR | Trade name and trademarks
Total Acquisition Date Fair Value
Indefinite-lived intangible assets	65,000
Customer relationships | CBR
Total Acquisition Date Fair Value
Finite-lived intangible assets	297,000
Favorable lease asset | CBR
Total Acquisition Date Fair Value
Finite-lived intangible assets	$ 358