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

- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

+ References+ Details

- Definition

The increase (decrease) in the recorded value of goodwill for foreign currency translation adjustments and purchase accounting adjustments needed to revise the carrying amount of goodwill to fair value.

+ References

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+ Details

Significant Accounting Policies (Details) (USD $)				12 Months Ended
Significant Accounting Policies (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Legacy Encore [Member]	Dec. 31, 2010 Legacy Encore [Member]	Dec. 31, 2011 Riley Ridge [Member]	Dec. 31, 2010 Riley Ridge [Member]	Dec. 31, 2011 Conroe Field [Member]	Dec. 31, 2010 Conroe Field [Member]
Changes in goodwill
Goodwill, Beginning Balance	$ 1,236,318,000	$ 1,232,418,000	$ 169,517,000
Goodwill, Adjustments								0	318,000
Goodwill acquired				0	1,061,123,000	3,900,000	1,460,000
Goodwill, Ending Balance	$ 1,236,318,000	$ 1,232,418,000	$ 169,517,000