Income Taxes - Reconciliation of Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax expense (benefit) based on Canadian statutory rates	$ 6.4	$ (8.7)	$ (10.1)
Foreign tax rate differential	(2.6)	(1.3)	(1.3)
Local taxes	0.5	(0.2)	(1.1)
Nontaxable interest income	(9.8)	(11.3)	(7.9)
Impact of intercompany transactions and dividends	1.0	(9.2)	(10.6)
Nontaxable capital gains	0.0	(3.7)	0.0
Dividend income	0.0	0.0	1.1
Change in enacted tax rates	3.4	(32.7)	(0.6)
Change in valuation allowance	(4.2)	45.8	48.6
Change in uncertain tax positions	(3.4)	(2.4)	(0.2)
Equity compensation	1.5	1.1	0.6
Permanent differences	1.1	(0.6)	1.8
Outside basis differences on discontinued operations	0.0	(3.8)	0.0
Adjustments to deferred taxes	0.7	(3.4)	0.0
Other items	0.6	0.4	0.9
Income tax (benefit) expense	$ (4.8)	$ (30.0)	$ 21.2