Consolidated Statement of Cash Flows (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statement of Cash Flows [Abstract]
Increase to property, plant and equipment	$ (466,115)	$ (386,462)	$ (352,674)
Changes in related accounts payable and accrued liabilities	(9,335)	791	(23,828)
Property, plant and equipment additions, net of equity AFUDC*	(475,450)	(385,671)	(376,502)
Supplemental disclosures of cash flow information:
Interest (exclusive of amount capitalized)	86,586	88,357	89,342
Income taxes	$ 254	$ 728	$ 31

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

The amount of cash paid for interest during the period net of cash paid for interest that is capitalized.

The cash outflow to purchase long lived physical asset for use in the normal oil and gas operations and to purchase mineral interests in oil and gas properties not intended for resale.

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- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

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