Employee Benefit Plans (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Benefit Plans
Expected return on plan assets (as a percent)	3.00%	3.50%
Plan Assets:
Total plan assets	$ 141.0	$ 123.9	$ 112.9
Contributions and Estimated Future Benefit Payments
2014	3.8
2015	4.0
2016	4.6
2017	4.8
2018	5.3
2019-2023	34.0
Company's contribution
Company's contributions to defined contribution plans	5.3	4.6	3.7
Maximum
Employee Benefit Plans
Discount rate (as a percent)	3.80%	4.10%	5.50%
Expected return on plan assets (as a percent)			4.00%
Expected rate of compensation increase (as a percent)	3.00%	3.80%	3.80%
Minimum
Employee Benefit Plans
Discount rate (as a percent)	0.70%	0.80%	1.10%
Expected return on plan assets (as a percent)			3.40%
Expected rate of compensation increase (as a percent)	1.00%	1.00%	1.00%
Cash and cash equivalents
Plan Assets:
Total plan assets	19.4	12.1
Debt securities:
Plan Assets:
Total plan assets	60.8	52.1
Debt securities: U.S. corporations
Plan Assets:
Total plan assets	1.4	1.3
Debt securities: Foreign corporations
Plan Assets:
Total plan assets	51.1	43.3
Debt securities: Foreign governments
Plan Assets:
Total plan assets	8.3	7.5
Equity Securities:
Plan Assets:
Total plan assets	40.4	37.8
Target allocations
Target allocation (as a percent)	30.00%
Equity Securities: Foreign corporations
Plan Assets:
Total plan assets	35.1	31.4
Equity Securities: U.S. corporations
Plan Assets:
Total plan assets	5.3	6.4
Real estate
Plan Assets:
Total plan assets	14.4	15.0
Mortgage and other asset-backed securities
Plan Assets:
Total plan assets	6.0	6.9
Bonds including cash
Target allocations
Target allocation (as a percent)	55.00%
Real estate and mortgages
Target allocations
Target allocation (as a percent)	15.00%
Quoted Prices in Active Markets Available (Level 1)
Plan Assets:
Total plan assets	135.0	117.0
Quoted Prices in Active Markets Available (Level 1) | Cash and cash equivalents
Plan Assets:
Total plan assets	19.4	12.1
Quoted Prices in Active Markets Available (Level 1) | Debt securities:
Plan Assets:
Total plan assets	60.8	52.1
Quoted Prices in Active Markets Available (Level 1) | Debt securities: U.S. corporations
Plan Assets:
Total plan assets	1.4	1.3
Quoted Prices in Active Markets Available (Level 1) | Debt securities: Foreign corporations
Plan Assets:
Total plan assets	51.1	43.3
Quoted Prices in Active Markets Available (Level 1) | Debt securities: Foreign governments
Plan Assets:
Total plan assets	8.3	7.5
Quoted Prices in Active Markets Available (Level 1) | Equity Securities:
Plan Assets:
Total plan assets	40.4	37.8
Quoted Prices in Active Markets Available (Level 1) | Equity Securities: Foreign corporations
Plan Assets:
Total plan assets	35.1	31.4
Quoted Prices in Active Markets Available (Level 1) | Equity Securities: U.S. corporations
Plan Assets:
Total plan assets	5.3	6.4
Quoted Prices in Active Markets Available (Level 1) | Real estate
Plan Assets:
Total plan assets	14.4	15.0
Significant Other Observable Inputs (Level 2)
Plan Assets:
Total plan assets	6.0	6.9
Significant Other Observable Inputs (Level 2) | Mortgage and other asset-backed securities
Plan Assets:
Total plan assets	$ 6.0	$ 6.9