Income taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income taxes

Summary of income tax expense

	For the year ended
	December 31,
	2017		2016
Current tax expense:
Current period	$	16.3	$	20.3
Adjustment for prior periods		2.3		6.7
		18.6		27.0
Deferred tax expense:
Origination and reversal of temporary differences		(38.0)		(4.4)
Change in unrecognized deductible temporary differences		5.2		1.4
Change in tax rate		0.3		(0.1)
Recognition of previously unrecognized tax losses		(122.4)		—
		(154.9)		(3.1)
Income tax expense (recovery)	$	(136.3)	$	23.9

Summary of reconciliation between statutory and effective income tax

	For the year ended
	December 31,
	2017			2016
Statutory Federal and Provincial tax rate in Canada		26.00	%		26.00	%
Income tax expense at the statutory tax rate	$	(9.3)		$	33.7
Foreign earnings subject to different rates		(13.0)			(6.1)
Change in statutory rates		3.9			—
Change in unrecognized deferred tax assets		(122.0)			(0.6)
Foreign exchange differences		(3.4)			(1.1)
Share-based compensation		2.3			1.8
Other permanent differences		5.2			(3.8)
	$	(136.3)		$	23.9

Summary of Unrecognized deferred tax assets

	December 31,		December 31,
	2017		2016
Tax losses	$	177.6	$	254.1
Other deductible temporary differences		90.4		138.3
	$	268.0	$	392.4

Summary of Recognized deferred tax assets and liabilities

December 31, 2017	Assets		Liabilities		Net
Construction contract assets and liabilities	$	87.6	$	(8.4)	$	79.2
Property, plant and equipment		177.8		(20.6)		157.2
Intangible assets and goodwill		9.2		(553.8)		(544.6)
Investment tax credits		11.1		(15.3)		(4.2)
Derivative financial instruments		5.0		(1.5)		3.5
Trade and other payables		26.6		—		26.6
Employee benefits		61.6		—		61.6
Tax loss carry forwards		216.9		—		216.9
Other items		11.2		(2.7)		8.5
Tax assets (liabilities)		607.0		(602.3)		4.7
Set off of tax		(498.7)		498.7		—
Net tax assets (liabilities)	$	108.3	$	(103.6)	$	4.7

December 31, 2016	Assets		Liabilities		Net
Construction contract assets and liabilities	$	4.3	$	(4.0)	$	0.3
Property, plant and equipment		0.1		(0.4)		(0.3)
Intangible assets and goodwill		0.8		(7.0)		(6.2)
Investment tax credits		8.3		(10.6)		(2.3)
Derivative financial instruments		0.2		(0.8)		(0.6)
Trade and other payables		2.3		—		2.3
Employee benefits		5.7		—		5.7
Tax loss carry forwards		4.7		—		4.7
Other items		0.2		(0.1)		0.1
Tax assets (liabilities)		26.6		(22.9)		3.7
Set off of tax		(11.6)		11.6		—
Net tax assets (liabilities)	$	15.0	$	(11.3)	$	3.7

Summary of movements of deferred tax assets and liabilities

					Recognized		Acquired in
	Balance,		Recognized		in other		business		Foreign		Balance,
	December 31,		in statement		comprehensive		combination		currency		December 31,
	2016		of earnings		income		(note 9)		translation		2017
Construction contract assets and liabilities	$	0.3	$	(46.3)	$	—	$	125.3	$	(0.1)	$	79.2
Property, plant and equipment		(0.3)		74.9		—		82.3		0.3		157.2
Intangible assets and goodwill		(6.2)		(12.9)		—		(525.0)		(0.5)		(544.6)
Investment tax credits		(2.3)		43.8		—		(45.7)		—		(4.2)
Derivative financial instruments		(0.6)		0.5		0.9		2.7		—		3.5
Trade and other payables		2.3		17.6		—		6.5		0.2		26.6
Employee benefits		5.7		43.9		(5.6)		17.3		0.3		61.6
Tax loss carry forwards		4.7		76.1		—		135.6		0.5		216.9
Other items		0.1		(42.7)		0.1		51.4		(0.4)		8.5
	$	3.7	$	154.9	$	(4.6)	$	(149.6)	$	0.3	$	4.7

					Recognized
	Balance,		Recognized		in other		Foreign		Balance,
	December 31,		in statement		comprehensive		currency		December 31,
	2015		of earnings		income		translation		2016
Construction contract assets and liabilities	$	1.1	$	(0.9)	$	—	$	0.1	$	0.3
Property, plant and equipment		0.2		(0.5)		—		—		(0.3)
Intangible assets and goodwill		(6.1)		0.1		—		(0.2)		(6.2)
Investment tax credits		(6.4)		4.4		—		(0.3)		(2.3)
Derivative financial instruments		(1.1)		0.4		0.1		—		(0.6)
Trade and other payables		3.7		(1.5)		—		0.1		2.3
Employee benefits		5.6		(0.7)		0.6		0.2		5.7
Tax loss carry forwards		2.3		2.4		—		—		4.7
Other items		0.6		(0.6)		—		0.1		0.1
	$	(0.1)	$	3.1	$	0.7	$	—	$	3.7

Summary of non-capital losses carried forward for tax purposes that are available to reduce taxable income of future years

2019	$	0.1
2026		1.1
2027		0.7
2028		9.7
2029		1.1
2030		41.6
2031		12.3
2032		171.9
2033		21.0
2034		15.6
2035		56.5
2036		60.2
2037		401.1
No Expiry		2.7
	$	795.6