Pension and Other Post-Retirement Benefit Plans (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans costs
Expense recognized related to 401(k) employee savings plans	$ 14,600,000	$ 12,000,000	$ 10,100,000
Pension Benefits
Defined Benefit Plans costs
Cash contributions to pension plan	2,639,000	2,857,000	4,300,000
Expected cash payments related to its pensions	400,000
Expected percentage of funding obligations met by cash contributions	80.00%
Benchmark percentage of funding obligations targeted to be met through cash contributions	80.00%
Defined benefit plan, expected future benefit payments in year 2014	2,500,000
Defined benefit plan, expected future benefit payments in year 2015	2,200,000
Defined benefit plan, expected future benefit payments in year 2016	2,000,000
Defined benefit plan, expected future benefit payments in year 2017	1,800,000
Defined benefit plan, expected future benefit payments in year 2018	1,900,000
Defined benefit plan, expected future benefit payments in the five years after 2018	8,400,000
Other Benefits
Defined Benefit Plans costs
Cash contributions to pension plan	328,000	146,000
Defined benefit plan, expected future benefit payments in year 2014	1,900,000
Defined benefit plan, expected future benefit payments in year 2015	1,800,000
Defined benefit plan, expected future benefit payments in year 2016	1,800,000
Defined benefit plan, expected future benefit payments in year 2017	1,700,000
Defined benefit plan, expected future benefit payments in year 2018	1,700,000
Defined benefit plan, expected future benefit payments in the five years after 2018	$ 7,700,000