Statement of Cash Flows (Unaudited) (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Statement of Cash Flows [Abstract]
Increases to property, plant and equipment	$ (17,463)	$ (11,234)
Changes in related accounts payable and accrued liabilities	(3,537)	(2,586)
Capital expenditures	$ (21,000)	$ (13,820)