Schedule Of Fair Values Of Pension Plan Assets By Asset Category (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 78.8		$ 70.5
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0		0.4
Equity Securities - Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14.3	[1]	13.0	[1]
Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9.8	[2]	9.2	[2]
US Government Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15.0	[3]	14.2	[3]
Global Multi-Strategy Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31.8	[4]	27.7	[4]
Insurance Investment Contract
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.3	[5]	4.7	[5]
Equity Securities, Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.6	[6]	1.3	[6]
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2.1		1.1
Fair Value, Inputs, Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.0		0.4
Fair Value, Inputs, Level 1 | Equity Securities - Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.9	[1]	0.4	[1]
Fair Value, Inputs, Level 1 | Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.1	[2]	0	[2]
Fair Value, Inputs, Level 1 | US Government Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[3]	0.1	[3]
Fair Value, Inputs, Level 1 | Global Multi-Strategy Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[4]	0	[4]
Fair Value, Inputs, Level 1 | Insurance Investment Contract
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[5]	0	[5]
Fair Value, Inputs, Level 1 | Equity Securities, Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.1	[6]	0.2	[6]
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	39.6		37.0
Fair Value, Inputs, Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		0
Fair Value, Inputs, Level 2 | Equity Securities - Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13.4	[1]	12.6	[1]
Fair Value, Inputs, Level 2 | Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9.7	[2]	9.2	[2]
Fair Value, Inputs, Level 2 | US Government Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15.0	[3]	14.1	[3]
Fair Value, Inputs, Level 2 | Global Multi-Strategy Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[4]	0	[4]
Fair Value, Inputs, Level 2 | Insurance Investment Contract
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[5]	0	[5]
Fair Value, Inputs, Level 2 | Equity Securities, Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.5	[6]	1.1	[6]
Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37.1		32.4
Fair Value, Inputs, Level 3 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		0
Fair Value, Inputs, Level 3 | Equity Securities - Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Fair Value, Inputs, Level 3 | Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[2]	0	[2]
Fair Value, Inputs, Level 3 | US Government Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[3]	0	[3]
Fair Value, Inputs, Level 3 | Global Multi-Strategy Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	31.8	[4]	27.7	[4]
Fair Value, Inputs, Level 3 | Insurance Investment Contract
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.3	[5]	4.7	[5]
Fair Value, Inputs, Level 3 | Equity Securities, Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	[6]	$ 0	[6]

[1] The equity securities represent mutual funds held by the pension plans in Canada, which include both domestic and international equity securities. Mutual funds are valued at quoted market prices, which represent the net asset values of shares held by the plans as of December 31, 2012.

[2] The bond funds constitutes investments primarily for the pension plans in Canada and the fund consists of investments in Canadian government, corporate and municipal or local governments bonds. Debt securities are valued at quoted market prices, where available.

[3] Government Fixed Income Securities-Government Fixed Income Securities are valued at the net asset value per share multiplied by the number of shares held as of the measurement.

[4] The global multi-strategy fund constitutes investments for the pension plans in the United Kingdom. The fund is a fund of funds invested in a series of diverse international equity funds and fixed income funds. The Global Multi-strategy fund is valued at quoted market prices which represent the net asset value of the units held at the December 31, 2012.

[5] The insurance investment contract is in the form of an insurance policy that is held by the pension plans in the United Kingdom. The investment of the underlying assets is in various managed funds. Insurance contracts are valued at book value, which approximates fair value, and are calculated using the prior year balance adjusted for investment returns and changes in cash flows.

[6] Other category includes money market funds and equity securities / international companies and mortgage-backed securities.