Commitments and Contingencies - Narrative (Detail) CAD in Millions, $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2017 CAD	Jul. 07, 2016 USD ($)
Loss Contingencies [Line Items]
Operating leases rent expense				$ 5.8	$ 5.4	$ 5.1
Rochester, New Hampshire
Loss Contingencies [Line Items]
Environmental remediation expense	$ 0.2
Texel | Quebec, Canada
Loss Contingencies [Line Items]
Indemnification assets, mimimum estimated outcome								$ 0.9
Indemnification assets, maximum estimated outcome								$ 1.5
Environment remediation indemnity secured by environmental escrow account			$ 2.4				CAD 3.0
Environmental remediation indemnity secured by general escrow account			11.1				14.0
Environmental remediation indemnity secured by general escrow account, reduced amount after share purchase agreement			5.6				CAD 7.0
Environmental Contamination | Rochester, New Hampshire
Loss Contingencies [Line Items]
Environmental liability			0.0
Reduction to accrual for environmental liability, payments			0.2
Accrual for environmental liability, including revision (fully offset)			0.2
Environmental Contamination | Texel | Quebec, Canada
Loss Contingencies [Line Items]
Environmental liability			0.8		$ 0.9
Accrual for environmental liability, revision of estimate		$ 0.6
Reduction to accrual for environmental liability, payments			0.7
Accrual for environmental liability, including revision (fully offset)		$ 1.5	$ 0.8