CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Property, plant and equipment, accumulated depreciation and amortization	$ 1,158,062	$ 1,129,669
Intangible assets, accumulated amortization	13,726	12,176
Deferred financing fees, accumulated amortization	$ 12,845	$ 11,750
Common stock, without par value	$ 0	$ 0
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	51,291,683	50,715,805
Common stock, shares outstanding	51,291,683	50,715,805