Property And Equipment (Property And Equipment By Classification) (Details) (USD $) In Thousands	Jun. 30, 2011	Sep. 30, 2010
Net book value	$ 1,813,674	$ 1,343,961
Drilling Vessels And Related Equipment [Member]
Cost	2,230,982	1,733,298
Accumulated depreciation	(420,237)	(392,808)
Net book value	1,810,745	1,340,490
Drill Pipe [Member]
Cost	15,468	15,468
Accumulated depreciation	(13,775)	(13,563)
Net book value	1,693	1,905
Furniture And Other [Member]
Cost	6,928	7,115
Accumulated depreciation	(5,692)	(5,549)
Net book value	$ 1,236	$ 1,566

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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