Pension and Other Post-Retirement Plans - Fair Value of Plan Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
U.K. Plan
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	$ 62.6		$ 52.1
U.K. Plan | Global return fund
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	19.4	[1]	17.7	[1]
U.K. Plan | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5.4	[1]	5.2	[1]
U.K. Plan | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	11.8		10.4	[1]
U.K. Plan | Cash
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.4	[2]	0.4	[1]
U.K. Plan | U.K | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	16.0	[1]	10.9	[1]
U.K. Plan | Other foreign countries | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	9.6	[1]	7.5	[1]
U.K. Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.4		0.4
U.K. Plan | Level 1 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total pension assets			0	[1]
U.K. Plan | Level 1 | Cash
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.4	[2]	0.4	[1]
U.K. Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	50.4		41.3
U.K. Plan | Level 2 | Global return fund
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	19.4	[1]	17.7	[1]
U.K. Plan | Level 2 | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5.4	[1]	5.2	[1]
U.K. Plan | Level 2 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total pension assets			0	[1]
U.K. Plan | Level 2 | U.K | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	16.0	[1]	10.9	[1]
U.K. Plan | Level 2 | Other foreign countries | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	9.6	[1]	7.5	[1]
U.K. Plan | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	11.8		10.4		9.3
U.K. Plan | Level 3 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	11.8		10.4	[1]
Canadian Plan
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	40.8		35.9
Canadian Plan | Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5.8		5.7
Canadian Plan | Other short-term investment
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.6	[3]	0.8	[3]
Canadian Plan | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.2	[4]	0.2	[4]
Canadian Plan | Canada | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	8.0	[5]	6.9	[5]
Canadian Plan | Canada | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	8.0		6.8
Canadian Plan | Other foreign countries | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	18.2	[5]	15.4	[5]
Canadian Plan | Other foreign countries | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0		0.1
Canadian Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	27.0		23.3
Canadian Plan | Level 1 | Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0		0
Canadian Plan | Level 1 | Other short-term investment
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.6	[3]	0.8
Canadian Plan | Level 1 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0.2	[4]	0.2	[4]
Canadian Plan | Level 1 | Canada | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	8.0	[5]	6.9	[5]
Canadian Plan | Level 1 | Canada | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0		0
Canadian Plan | Level 1 | Other foreign countries | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	18.2	[5]	15.4	[5]
Canadian Plan | Level 1 | Other foreign countries | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0
Canadian Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	13.8		12.6
Canadian Plan | Level 2 | Government bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	5.8		5.7
Canadian Plan | Level 2 | Other short-term investment
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0	[3]	0	[3]
Canadian Plan | Level 2 | Canada | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0	[5]	0	[5]
Canadian Plan | Level 2 | Canada | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	8.0		6.8
Canadian Plan | Level 2 | Other foreign countries | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	0	[5]	0	[5]
Canadian Plan | Level 2 | Other foreign countries | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Total pension assets	$ 0		$ 0.1

[1] The assets are invested through managed funds that are valued using inputs derived principally from quoted prices in active markets for the underlying assets in the fund.

[2] The fair value of cash equals its book value.

[3] Other short-term investments are investments in pooled money market funds that are valued using inputs derived principally from the quoted prices in active markets for the underlying assets in the pool.

[4] The carrying value of cash and cash equivalents approximates fair value because of the short-term maturity of these instruments.

[5] Direct investments in equity securities are valued at quoted prices in active markets for identical assets. Equity securities invested through pooled funds are valued using inputs derived principally from the quoted prices in active markets for the underlying assets in the pool.