PROPERTY, PLANT AND EQUIPMENT - Property and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
Jun. 30, 2019	Sep. 30, 2018
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment, gross	$ 9,186,315	$ 9,146,247
Accumulated depreciation	(4,602,642)	(4,288,865)
Property, plant and equipment, net	4,583,673	4,857,382
Contract drilling equipment
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment, gross	$ 8,486,332	8,442,081
Contract drilling equipment \| Minimum
PROPERTY, PLANT AND EQUIPMENT
Estimated useful lives	4 years
Contract drilling equipment \| Maximum
PROPERTY, PLANT AND EQUIPMENT
Estimated useful lives	15 years
Real estate properties
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment, gross	$ 71,114	68,888
Real estate properties \| Minimum
PROPERTY, PLANT AND EQUIPMENT
Estimated useful lives	10 years
Real estate properties \| Maximum
PROPERTY, PLANT AND EQUIPMENT
Estimated useful lives	45 years
Other
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment, gross	$ 469,933	471,310
Other \| Minimum
PROPERTY, PLANT AND EQUIPMENT
Estimated useful lives	2 years
Other \| Maximum
PROPERTY, PLANT AND EQUIPMENT
Estimated useful lives	23 years
Construction in progress
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment, gross	$ 158,936	$ 163,968

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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-Name Accounting Standards Codification
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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Section 50
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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

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