Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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+ Details

Goodwill by Operating Segment (Detail) (USD $) In Thousands	9 Months Ended
Goodwill by Operating Segment (Detail) (USD $) In Thousands	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Goodwill [Line Items]
Goodwill	$ 153,809	$ 86,234	$ 153,809	$ 86,234
Changes to Goodwill
Contract Drilling
Goodwill [Line Items]
Goodwill, gross	86,234	86,234	86,234	86,234
Accumulated impairment losses
Goodwill	86,234	86,234	86,234	86,234
Changes to Goodwill
Pressure Pumping
Goodwill [Line Items]
Goodwill, gross	67,575		67,575
Accumulated impairment losses
Goodwill	67,575		67,575
Changes to Goodwill