Property And Equipment (A Summary Of Property And Equipment By Classification) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Sep. 30, 2011
Property, Plant and Equipment [Line Items]
Cost	$ 2,872,893	$ 2,342,401
Less: Accumulated depreciation	(500,447)	(455,080)
Drilling and other property and equipment, net	2,372,446	1,887,321
Drilling Vessels And Equipment [Member]
Property, Plant and Equipment [Line Items]
Cost	1,624,065	1,578,592
Construction Work In Progress [Member]
Property, Plant and Equipment [Line Items]
Cost	1,212,129	736,827
Drill Pipe [Member]
Property, Plant and Equipment [Line Items]
Cost	19,407	18,182
Office Equipment And Other [Member]
Property, Plant and Equipment [Line Items]
Cost	$ 17,292	$ 8,800

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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