Drilling and Other Property and Equipment (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Summary of cost and accumulated depreciation of drilling and other property and equipment
Drilling rigs and equipment	$ 7,235,894	$ 7,163,196
Land and buildings	60,027	56,536
Office equipment and other	46,509	44,689
Cost	7,342,430	7,264,421
Less: accumulated depreciation	(3,182,888)	(2,980,629)
Drilling and other property and equipment, net	$ 4,159,542	$ 4,283,792

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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