Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Tax Disclosure [Abstract]

Income tax expense reported reconciliation to computed statutory rate

The income tax expense reported differs from the amount computed by applying the U.S. statutory rate to income before income taxes for the following reasons:

	Year Ended December 31,
(Thousands of U.S. Dollars)	2011				2010				2009
Income before income taxes	$	234,247			$	94,406				38,295
		35		%		35		%		35	%
Income tax expense expected		81,986				33,042				13,403
Foreign currency translation adjustments		(417	)			6,409				1,099
Impact of foreign taxes		3,890				(3,094	)			(1,565	)
Enhanced tax depreciation incentive		-				(7,971	)			(3,380	)
Stock-based compensation		4,013				2,381				1,814
Increase in valuation allowance		36,815				19,991				16,199
Branch and other foreign income pick-up in the United States and Canada		(14,363	)			(3,957	)			(5,931	)
Non-deductible third party royalty in Colombia		8,525				5,506				3,532
Non-taxable gain on acquisition		(7,595	)			-				-
Other permanent differences		(5,524	)			4,927				(817	)
Total income tax expense	$	107,330			$	57,234			$	24,354
Current income tax		136,015				76,913				38,795
Deferred tax recovery		(28,685	)			(19,679	)			(14,441	)
Total income tax expense	$	107,330			$	57,234			$	24,354

Deferred tax assets and liabilities

	As at December 31,
(Thousands of U.S. Dollars)	2011			2010
Deferred Tax Assets
Tax benefit of loss carryforwards	$	63,910		$	27,527
Tax basis in excess of book basis		17,065			7,975
Foreign tax credits and other accruals		27,164			16,895
Capital losses		2,433			1,413
Deferred tax assets before valuation allowance		110,572			53,810
Valuation allowance		(102,796	)		(48,958	)
	$	7,776		$	4,852
Deferred tax assets - current	$	3,029		$	4,852
Deferred tax assets - long-term		4,747			-
		7,776			4,852
Deferred Tax Liabilities
Long-term - book value in excess of tax basis		(186,799	)		(204,570	)
		(186,799	)		(204,570	)
Net Deferred Tax Liabilities	$	(179,023	)	$	(199,718	)

Changes in the company's unrecognized tax benefit are as follows

Changes in the Company's unrecognized tax benefit are as follows:

(Thousands of U.S. Dollars)
Unrecognized tax benefit at January 1, 2011	$	4,175
Changes for tax positions relating to prior year		585
Additions to tax position related to the current year		15,740
Unrecognized tax benefit at December 31, 2011	$	20,500