Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Increase in deferred tax assets	$ 0.9	$ 7.4
Impact of change in tax rate related to Finance Act 2021			$ (8.3)	$ 0.0	$ 0.0
Net operating losses carryback period			2 years
Capital losses carryback period			3 years
Net change in valuation allowance, for deferred tax asset			$ (0.7)
Unrecognized tax benefits	3.6		3.6	8.2	7.5
Decrease in unrecognized tax benefits is reasonably possible	$ 0.6		0.6
Unrecognized tax benefits, interest expense on income taxes			(1.0)	0.5	0.5
Tax penalty expense			$ (0.8)	$ 0.1	$ 0.2