Taxes (Tables)

12 Months Ended

Dec. 31, 2012

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)	2012			2011			2010
Income (loss) before income taxes
United States	(13,918		)	4,984			(16,726		)
Foreign	211,281			229,263			111,132
	197,363			234,247			94,406
	35		%	35		%	35		%
Income tax expense expected	69,077			81,986			33,042
Foreign currency translation adjustments	5,473			(417		)	6,409
Impact of foreign taxes	(1,833		)	3,890			(3,094		)
Stock-based compensation	3,982			4,013			2,381
Increase in valuation allowance	6,709			36,815			19,991
Branch and other foreign loss pick-up	(3,809		)	(14,363		)	(3,957		)
Non-deductible third party royalty in Colombia	11,938			8,525			5,506
Enhanced tax depreciation incentive	—			—			(7,971		)
Non-taxable gain on acquisition	—			(7,595		)	—
Other permanent differences	6,167			(5,524		)	4,927
Total income tax expense	$	97,704		$	107,330		$	57,234
Current income tax expense
United States	1,233			1,029			501
Foreign	70,197			134,986			76,412
	71,430			136,015			76,913
Deferred income tax expense (recovery)
United States	—			—			—
Foreign	26,274			(28,685		)	(19,679		)
	26,274			(28,685		)	(19,679		)
Total income tax expense	$	97,704		$	107,330		$	57,234

Deferred tax assets and liabilities

	As at December 31,
(Thousands of U.S. Dollars)	2012			2011
Deferred Tax Assets
Tax benefit of loss carryforwards	$	51,920		$	63,910
Tax basis in excess of book basis	22,519			17,065
Foreign tax credits and other accruals	30,926			27,164
Capital losses	4,779			2,433
Deferred tax assets before valuation allowance	110,144			110,572
Valuation allowance	(106,226		)	(102,796		)
	$	3,918		$	7,776
Deferred tax assets - current	$	2,517		$	3,029
Deferred tax assets - long-term	1,401			4,747
	3,918			7,776
Deferred tax liabilities - current	(337		)	—
Deferred tax liabilities - long-term	(225,195		)	(186,799		)
	$	(225,532	)	$	(186,799	)
Net Deferred Tax Liabilities	$	(221,614	)	$	(179,023	)

Summary of Other Tax Carryforwards

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

	Year Ended December 31,
	2012		2011
(Thousands of U.S. Dollars)
Unrecognized tax benefit, beginning of year	$	20,500	$	4,175
Changes for positions relating to prior year	1,300		585
Additions to tax position related to the current year	—		15,740
Unrecognized tax benefit, end of year	$	21,800	$	20,500