Employee Benefit Plans (Details 2) (Employee Pension Plans, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Pension Plan Assets
Target asset allocation (as a percent)	100.00%
Actual asset allocation (as a percent)	100.00%	100.00%
Expected contributions to the defined benefit pension plan in 2014	$ 2.8
Hedge Funds
Pension Plan Assets
Investments in hedge funds which do not have readily determinable fair values	$ 44.7	$ 44.3
Cash and Cash Equivalents
Pension Plan Assets
Target asset allocation (as a percent)	5.00%
Actual asset allocation (as a percent)	5.20%	6.60%
Domestic Equity Securities
Pension Plan Assets
Target asset allocation (as a percent)	65.00%
Actual asset allocation (as a percent)	63.40%	67.50%
International Equity Securities
Pension Plan Assets
Target asset allocation (as a percent)	25.00%
Actual asset allocation (as a percent)	25.90%	20.80%
Fixed Income Securities
Pension Plan Assets
Target asset allocation (as a percent)	5.00%
Actual asset allocation (as a percent)	5.50%	5.10%