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International Risk Factors (Details) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($) item	Mar. 31, 2016 USD ($)	Jun. 30, 2010 item
International Risk Factors
Foreign currency losses | $	$ 0.6	$ (0.2)	$ 2.0	$ 8.3
Period for which cumulative inflation rates used for considering country as highly inflationary			3 years
Venezuela
International Risk Factors
Number of rigs expropriated by Venezuelan government | item					11
Argentina
International Risk Factors
Foreign currency losses | $				$ 8.3
Operating revenues | Geographic concentration risk | South America
International Risk Factors
Concentration percentage			87.10%
Minimum
International Risk Factors
Number of geographical areas of operation to minimize risks | item			1
Cumulative inflation rate before a country is considered highly inflationary (as a percent)			100.00%
Contract Drilling: | Operating revenues | Geographic concentration risk | International locations
International Risk Factors
Concentration percentage			13.30%

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Represents the cumulative inflation rate before a country is considered highly inflationary.

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Represents the number of geographical areas operated to minimize the potential impact of risks.

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The number of rigs which were expropriated by the Government.

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Represents the period over which cumulative inflation rates are used in considering whether a country is highly inflationary.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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